diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2dce60c7..a27eaa19 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ## [Unreleased] - 2021-06-10
 
 ### Added
+- Group: [add Group-API](https://github.com/5pm-HDH/churchtools-api/pull/47)
 
 ### Changed
 - Refactoring: [refactor Code, introduce namespace to test-suites, update phpunit-configuration](https://github.com/5pm-HDH/churchtools-api/pull/46)
diff --git a/README.md b/README.md
index de8ff86c..292d78bd 100644
--- a/README.md
+++ b/README.md
@@ -52,6 +52,7 @@ the Requests retrieve. More informations can be found in the documentation.
 
 All APIs with examples:
 * [Person-API](/docs/PersonAPI.md)
+* [Group-API](/docs/GroupAPI.md)
 * [Event-API](/docs/EventAPI.md)
 * [Song-API](/docs/SongAPI.md)
 * [Service-API](/docs/ServiceAPI.md)
diff --git a/docs/GroupAPI.md b/docs/GroupAPI.md
new file mode 100644
index 00000000..ef910864
--- /dev/null
+++ b/docs/GroupAPI.md
@@ -0,0 +1,82 @@
+# GroupAPI
+
+```php
+use CTApi\Requests\GroupRequest;use CTApi\Requests\PersonRequest;
+
+/**
+ * Group-Request
+ */
+ 
+// Retrieve all groups
+$allGroups = GroupRequest::all();
+$allGroups = GroupRequest::orderBy('name')->get();
+
+$myGroups = PersonRequest::whoami()?->requestGroups();
+
+// Get specific Group
+$group = GroupRequest::find(21);     // returns "null" if id is invalid
+$group = GroupRequest::findOrFail(22); // throws exception if id is invalid
+
+
+/**
+ * Group-Data
+ */
+echo "-".$group->getId();
+echo "-".$group->getGuid();
+echo "-".$group->getName();
+print_r($group->getSecurityLevelForGroup());
+print_r($group->getPermissions());
+print_r($group->getInformation());
+print_r($group->getFollowUp());
+print_r($group->getRoles());
+
+echo "GroupSettings\n";
+echo "-".$group->getSettings()?->getIsHidden();
+echo "-".$group->getSettings()?->getIsOpenForMembers();
+echo "-".$group->getSettings()?->getAllowSpouseRegistration();
+echo "-".$group->getSettings()?->getAllowChildRegistration();
+echo "-".$group->getSettings()?->getAllowSameEmailRegistration();
+echo "-".$group->getSettings()?->getAutoAccept();
+echo "-".$group->getSettings()?->getAllowWaitinglist();
+echo "-".$group->getSettings()?->getWaitinglistMaxPersons();
+echo "-".$group->getSettings()?->getAutomaticMoveUp();
+echo "-".$group->getSettings()?->getIsPublic();
+print_r($group->getSettings()?->getGroupMeeting());
+echo "-".$group->getSettings()?->getQrCodeCheckin();
+print_r($group->getSettings()?->getNewMember());
+
+echo "GroupRoles\n";
+$groupRole = $group->getRoles()[0];
+echo "-".$groupRole->getId();
+echo "-".$groupRole->getGroupTypeId();
+echo "-".$groupRole->getName();
+echo "-".$groupRole->getShorty();
+echo "-".$groupRole->getShortKey();
+echo "-".$groupRole->getToDelete();
+echo "-".$groupRole->getHasRequested();
+echo "-".$groupRole->getIsLeader();
+echo "-".$groupRole->getIsDefault();
+echo "-".$groupRole->getIsHidden();
+echo "-".$groupRole->getGrowPathId();
+echo "-".$groupRole->getGroupTypeRoleId();
+echo "-".$groupRole->getForceTwoFactorAuth();
+echo "-".$groupRole->getIsActive();
+echo "-".$groupRole->getCanReadChat();
+echo "-".$groupRole->getCanWriteChat();
+
+echo "GroupMembers";
+$groupMember = $group->requestMembers()[0];
+
+echo "-".$groupMember->getId();
+echo "-".$groupMember->getPersonId();
+echo "-".$groupMember->getGroupTypeRoleId();
+echo "-".$groupMember->getMemberStartDate();
+echo "-".$groupMember->getComment();
+echo "-".$groupMember->getMemberEndDate();
+echo "-".$groupMember->getWaitinglistPosition();
+print_r($groupMember->getFields());
+
+$personGroupMember = $groupMember->getPerson();
+$personGroupMember = $groupMember->requestPerson();
+
+```
\ No newline at end of file
diff --git a/src/Models/Group.php b/src/Models/Group.php
new file mode 100644
index 00000000..6a04fb28
--- /dev/null
+++ b/src/Models/Group.php
@@ -0,0 +1,224 @@
+<?php
+
+
+namespace CTApi\Models;
+
+
+use CTApi\Models\Traits\FillWithData;
+use CTApi\Requests\GroupMemberRequestBuilder;
+
+class Group
+{
+    use FillWithData;
+
+    protected ?string $id = null;
+    protected ?string $guid = null;
+    protected ?string $name = null;
+    protected ?string $securityLevelForGroup = null;
+    protected array $permissions = [];
+    protected array $information = [];
+    protected ?GroupSettings $settings = null;
+    protected array $followUp = [];
+    protected array $roles = [];
+
+
+    protected function fillNonArrayType(string $key, $value)
+    {
+        switch ($key) {
+            case "title":
+                $this->setName($value);
+                break;
+            case "domainIdentifier":
+                $this->setId($value);
+                break;
+            default:
+                $this->{$key} = $value;
+        }
+    }
+
+    protected function fillArrayType(string $key, array $data)
+    {
+        switch ($key) {
+            case "roles":
+                $this->setRoles(GroupRole::createModelsFromArray($data));
+                break;
+            case "settings":
+                $this->setSettings(GroupSettings::createModelFromData($data));
+                break;
+            default:
+                $this->{$key} = $data;
+        }
+    }
+
+
+    public function requestMembers(): ?GroupMemberRequestBuilder
+    {
+        if ($this->getId() != null) {
+            return new GroupMemberRequestBuilder((int)$this->getId());
+        } else {
+            return null;
+        }
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getId(): ?string
+    {
+        return $this->id;
+    }
+
+    /**
+     * @param string|null $id
+     * @return Group
+     */
+    public function setId(?string $id): Group
+    {
+        $this->id = $id;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getGuid(): ?string
+    {
+        return $this->guid;
+    }
+
+    /**
+     * @param string|null $guid
+     * @return Group
+     */
+    public function setGuid(?string $guid): Group
+    {
+        $this->guid = $guid;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getName(): ?string
+    {
+        return $this->name;
+    }
+
+    /**
+     * @param string|null $name
+     * @return Group
+     */
+    public function setName(?string $name): Group
+    {
+        $this->name = $name;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getSecurityLevelForGroup(): ?string
+    {
+        return $this->securityLevelForGroup;
+    }
+
+    /**
+     * @param string|null $securityLevelForGroup
+     * @return Group
+     */
+    public function setSecurityLevelForGroup(?string $securityLevelForGroup): Group
+    {
+        $this->securityLevelForGroup = $securityLevelForGroup;
+        return $this;
+    }
+
+    /**
+     * @return array
+     */
+    public function getPermissions(): array
+    {
+        return $this->permissions;
+    }
+
+    /**
+     * @param array $permissions
+     * @return Group
+     */
+    public function setPermissions(array $permissions): Group
+    {
+        $this->permissions = $permissions;
+        return $this;
+    }
+
+    /**
+     * @return array
+     */
+    public function getInformation(): array
+    {
+        return $this->information;
+    }
+
+    /**
+     * @param array $information
+     * @return Group
+     */
+    public function setInformation(array $information): Group
+    {
+        $this->information = $information;
+        return $this;
+    }
+
+    /**
+     * @return GroupSettings|null
+     */
+    public function getSettings(): ?GroupSettings
+    {
+        return $this->settings;
+    }
+
+    /**
+     * @param GroupSettings|null $settings
+     * @return Group
+     */
+    public function setSettings(?GroupSettings $settings): Group
+    {
+        $this->settings = $settings;
+        return $this;
+    }
+
+    /**
+     * @return array
+     */
+    public function getFollowUp(): array
+    {
+        return $this->followUp;
+    }
+
+    /**
+     * @param array $followUp
+     * @return Group
+     */
+    public function setFollowUp(array $followUp): Group
+    {
+        $this->followUp = $followUp;
+        return $this;
+    }
+
+    /**
+     * @return array
+     */
+    public function getRoles(): array
+    {
+        return $this->roles;
+    }
+
+    /**
+     * @param array $roles
+     * @return Group
+     */
+    public function setRoles(array $roles): Group
+    {
+        $this->roles = $roles;
+        return $this;
+    }
+}
\ No newline at end of file
diff --git a/src/Models/GroupMember.php b/src/Models/GroupMember.php
new file mode 100644
index 00000000..e4eadefb
--- /dev/null
+++ b/src/Models/GroupMember.php
@@ -0,0 +1,206 @@
+<?php
+
+
+namespace CTApi\Models;
+
+
+use CTApi\Models\Traits\FillWithData;
+use CTApi\Requests\PersonRequest;
+
+class GroupMember
+{
+    use FillWithData;
+
+    protected ?string $id = null;
+    protected ?string $personId = null;
+    protected ?Person $person = null;
+    protected ?string $groupTypeRoleId = null;
+    protected ?string $memberStartDate = null;
+    protected ?string $comment = null;
+    protected ?string $memberEndDate = null;
+    protected ?string $waitinglistPosition = null;
+    protected array $fields = [];
+
+
+    protected function fillArrayType(string $key, array $data)
+    {
+        switch ($key) {
+            case "person":
+                $this->setPerson(Person::createModelFromData($data));
+                break;
+            default:
+                $this->{$key} = $data;
+        }
+    }
+
+    public function requestPerson(): ?Person
+    {
+        if ($this->getPersonId() != null) {
+            return PersonRequest::find($this->getPersonId());
+        } else {
+            return null;
+        }
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getId(): ?string
+    {
+        return $this->id;
+    }
+
+    /**
+     * @param string|null $id
+     * @return GroupMember
+     */
+    public function setId(?string $id): GroupMember
+    {
+        $this->id = $id;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getPersonId(): ?string
+    {
+        return $this->personId;
+    }
+
+    /**
+     * @param string|null $personId
+     * @return GroupMember
+     */
+    public function setPersonId(?string $personId): GroupMember
+    {
+        $this->personId = $personId;
+        return $this;
+    }
+
+    /**
+     * @return Person|null
+     */
+    public function getPerson(): ?Person
+    {
+        return $this->person;
+    }
+
+    /**
+     * @param Person|null $person
+     * @return GroupMember
+     */
+    public function setPerson(?Person $person): GroupMember
+    {
+        $this->person = $person;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getGroupTypeRoleId(): ?string
+    {
+        return $this->groupTypeRoleId;
+    }
+
+    /**
+     * @param string|null $groupTypeRoleId
+     * @return GroupMember
+     */
+    public function setGroupTypeRoleId(?string $groupTypeRoleId): GroupMember
+    {
+        $this->groupTypeRoleId = $groupTypeRoleId;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getMemberStartDate(): ?string
+    {
+        return $this->memberStartDate;
+    }
+
+    /**
+     * @param string|null $memberStartDate
+     * @return GroupMember
+     */
+    public function setMemberStartDate(?string $memberStartDate): GroupMember
+    {
+        $this->memberStartDate = $memberStartDate;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getComment(): ?string
+    {
+        return $this->comment;
+    }
+
+    /**
+     * @param string|null $comment
+     * @return GroupMember
+     */
+    public function setComment(?string $comment): GroupMember
+    {
+        $this->comment = $comment;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getMemberEndDate(): ?string
+    {
+        return $this->memberEndDate;
+    }
+
+    /**
+     * @param string|null $memberEndDate
+     * @return GroupMember
+     */
+    public function setMemberEndDate(?string $memberEndDate): GroupMember
+    {
+        $this->memberEndDate = $memberEndDate;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getWaitinglistPosition(): ?string
+    {
+        return $this->waitinglistPosition;
+    }
+
+    /**
+     * @param string|null $waitinglistPosition
+     * @return GroupMember
+     */
+    public function setWaitinglistPosition(?string $waitinglistPosition): GroupMember
+    {
+        $this->waitinglistPosition = $waitinglistPosition;
+        return $this;
+    }
+
+    /**
+     * @return array
+     */
+    public function getFields(): array
+    {
+        return $this->fields;
+    }
+
+    /**
+     * @param array $fields
+     * @return GroupMember
+     */
+    public function setFields(array $fields): GroupMember
+    {
+        $this->fields = $fields;
+        return $this;
+    }
+}
\ No newline at end of file
diff --git a/src/Models/GroupRole.php b/src/Models/GroupRole.php
new file mode 100644
index 00000000..72742617
--- /dev/null
+++ b/src/Models/GroupRole.php
@@ -0,0 +1,318 @@
+<?php
+
+
+namespace CTApi\Models;
+
+
+use CTApi\Models\Traits\FillWithData;
+
+class GroupRole
+{
+    use FillWithData;
+
+    protected ?string $id = null;
+    protected ?string $groupTypeId = null;
+    protected ?string $name = null;
+    protected ?string $shorty = null;
+    protected ?string $sortKey = null;
+    protected ?string $toDelete = null;
+    protected ?string $hasRequested = null;
+    protected ?string $isLeader = null;
+    protected ?string $isDefault = null;
+    protected ?string $isHidden = null;
+    protected ?string $growPathId = null;
+    protected ?string $groupTypeRoleId = null;
+    protected ?string $forceTwoFactorAuth = null;
+    protected ?string $isActive = null;
+    protected ?string $canReadChat = null;
+    protected ?string $canWriteChat = null;
+
+    /**
+     * @return string|null
+     */
+    public function getId(): ?string
+    {
+        return $this->id;
+    }
+
+    /**
+     * @param string|null $id
+     * @return GroupRole
+     */
+    public function setId(?string $id): GroupRole
+    {
+        $this->id = $id;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getGroupTypeId(): ?string
+    {
+        return $this->groupTypeId;
+    }
+
+    /**
+     * @param string|null $groupTypeId
+     * @return GroupRole
+     */
+    public function setGroupTypeId(?string $groupTypeId): GroupRole
+    {
+        $this->groupTypeId = $groupTypeId;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getName(): ?string
+    {
+        return $this->name;
+    }
+
+    /**
+     * @param string|null $name
+     * @return GroupRole
+     */
+    public function setName(?string $name): GroupRole
+    {
+        $this->name = $name;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getShorty(): ?string
+    {
+        return $this->shorty;
+    }
+
+    /**
+     * @param string|null $shorty
+     * @return GroupRole
+     */
+    public function setShorty(?string $shorty): GroupRole
+    {
+        $this->shorty = $shorty;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getSortKey(): ?string
+    {
+        return $this->sortKey;
+    }
+
+    /**
+     * @param string|null $sortKey
+     * @return GroupRole
+     */
+    public function setSortKey(?string $sortKey): GroupRole
+    {
+        $this->sortKey = $sortKey;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getToDelete(): ?string
+    {
+        return $this->toDelete;
+    }
+
+    /**
+     * @param string|null $toDelete
+     * @return GroupRole
+     */
+    public function setToDelete(?string $toDelete): GroupRole
+    {
+        $this->toDelete = $toDelete;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getHasRequested(): ?string
+    {
+        return $this->hasRequested;
+    }
+
+    /**
+     * @param string|null $hasRequested
+     * @return GroupRole
+     */
+    public function setHasRequested(?string $hasRequested): GroupRole
+    {
+        $this->hasRequested = $hasRequested;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getIsLeader(): ?string
+    {
+        return $this->isLeader;
+    }
+
+    /**
+     * @param string|null $isLeader
+     * @return GroupRole
+     */
+    public function setIsLeader(?string $isLeader): GroupRole
+    {
+        $this->isLeader = $isLeader;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getIsDefault(): ?string
+    {
+        return $this->isDefault;
+    }
+
+    /**
+     * @param string|null $isDefault
+     * @return GroupRole
+     */
+    public function setIsDefault(?string $isDefault): GroupRole
+    {
+        $this->isDefault = $isDefault;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getIsHidden(): ?string
+    {
+        return $this->isHidden;
+    }
+
+    /**
+     * @param string|null $isHidden
+     * @return GroupRole
+     */
+    public function setIsHidden(?string $isHidden): GroupRole
+    {
+        $this->isHidden = $isHidden;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getGrowPathId(): ?string
+    {
+        return $this->growPathId;
+    }
+
+    /**
+     * @param string|null $growPathId
+     * @return GroupRole
+     */
+    public function setGrowPathId(?string $growPathId): GroupRole
+    {
+        $this->growPathId = $growPathId;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getGroupTypeRoleId(): ?string
+    {
+        return $this->groupTypeRoleId;
+    }
+
+    /**
+     * @param string|null $groupTypeRoleId
+     * @return GroupRole
+     */
+    public function setGroupTypeRoleId(?string $groupTypeRoleId): GroupRole
+    {
+        $this->groupTypeRoleId = $groupTypeRoleId;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getForceTwoFactorAuth(): ?string
+    {
+        return $this->forceTwoFactorAuth;
+    }
+
+    /**
+     * @param string|null $forceTwoFactorAuth
+     * @return GroupRole
+     */
+    public function setForceTwoFactorAuth(?string $forceTwoFactorAuth): GroupRole
+    {
+        $this->forceTwoFactorAuth = $forceTwoFactorAuth;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getIsActive(): ?string
+    {
+        return $this->isActive;
+    }
+
+    /**
+     * @param string|null $isActive
+     * @return GroupRole
+     */
+    public function setIsActive(?string $isActive): GroupRole
+    {
+        $this->isActive = $isActive;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getCanReadChat(): ?string
+    {
+        return $this->canReadChat;
+    }
+
+    /**
+     * @param string|null $canReadChat
+     * @return GroupRole
+     */
+    public function setCanReadChat(?string $canReadChat): GroupRole
+    {
+        $this->canReadChat = $canReadChat;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getCanWriteChat(): ?string
+    {
+        return $this->canWriteChat;
+    }
+
+    /**
+     * @param string|null $canWriteChat
+     * @return GroupRole
+     */
+    public function setCanWriteChat(?string $canWriteChat): GroupRole
+    {
+        $this->canWriteChat = $canWriteChat;
+        return $this;
+    }
+
+}
\ No newline at end of file
diff --git a/src/Models/GroupSettings.php b/src/Models/GroupSettings.php
new file mode 100644
index 00000000..c5c0a403
--- /dev/null
+++ b/src/Models/GroupSettings.php
@@ -0,0 +1,279 @@
+<?php
+
+
+namespace CTApi\Models;
+
+
+use CTApi\Models\Traits\FillWithData;
+
+class GroupSettings
+{
+    use FillWithData;
+
+    protected ?string $isHidden = null;
+    protected ?string $isOpenForMembers = null;
+    protected ?string $allowSpouseRegistration = null;
+    protected ?string $allowChildRegistration = null;
+    protected ?string $allowSameEmailRegistration = null;
+    protected ?string $allowOtherRegistration = null;
+    protected ?string $autoAccept = null;
+    protected ?string $allowWaitinglist = null;
+    protected ?string $waitinglistMaxPersons = null;
+    protected ?string $automaticMoveUp = null;
+    protected ?string $isPublic = null;
+    protected array $groupMeeting = [];
+    protected ?string $qrCodeCheckin = null;
+    protected array $newMember = [];
+
+    /**
+     * @return string|null
+     */
+    public function getIsHidden(): ?string
+    {
+        return $this->isHidden;
+    }
+
+    /**
+     * @param string|null $isHidden
+     * @return GroupSettings
+     */
+    public function setIsHidden(?string $isHidden): GroupSettings
+    {
+        $this->isHidden = $isHidden;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getIsOpenForMembers(): ?string
+    {
+        return $this->isOpenForMembers;
+    }
+
+    /**
+     * @param string|null $isOpenForMembers
+     * @return GroupSettings
+     */
+    public function setIsOpenForMembers(?string $isOpenForMembers): GroupSettings
+    {
+        $this->isOpenForMembers = $isOpenForMembers;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getAllowSpouseRegistration(): ?string
+    {
+        return $this->allowSpouseRegistration;
+    }
+
+    /**
+     * @param string|null $allowSpouseRegistration
+     * @return GroupSettings
+     */
+    public function setAllowSpouseRegistration(?string $allowSpouseRegistration): GroupSettings
+    {
+        $this->allowSpouseRegistration = $allowSpouseRegistration;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getAllowChildRegistration(): ?string
+    {
+        return $this->allowChildRegistration;
+    }
+
+    /**
+     * @param string|null $allowChildRegistration
+     * @return GroupSettings
+     */
+    public function setAllowChildRegistration(?string $allowChildRegistration): GroupSettings
+    {
+        $this->allowChildRegistration = $allowChildRegistration;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getAllowSameEmailRegistration(): ?string
+    {
+        return $this->allowSameEmailRegistration;
+    }
+
+    /**
+     * @param string|null $allowSameEmailRegistration
+     * @return GroupSettings
+     */
+    public function setAllowSameEmailRegistration(?string $allowSameEmailRegistration): GroupSettings
+    {
+        $this->allowSameEmailRegistration = $allowSameEmailRegistration;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getAllowOtherRegistration(): ?string
+    {
+        return $this->allowOtherRegistration;
+    }
+
+    /**
+     * @param string|null $allowOtherRegistration
+     * @return GroupSettings
+     */
+    public function setAllowOtherRegistration(?string $allowOtherRegistration): GroupSettings
+    {
+        $this->allowOtherRegistration = $allowOtherRegistration;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getAutoAccept(): ?string
+    {
+        return $this->autoAccept;
+    }
+
+    /**
+     * @param string|null $autoAccept
+     * @return GroupSettings
+     */
+    public function setAutoAccept(?string $autoAccept): GroupSettings
+    {
+        $this->autoAccept = $autoAccept;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getAllowWaitinglist(): ?string
+    {
+        return $this->allowWaitinglist;
+    }
+
+    /**
+     * @param string|null $allowWaitinglist
+     * @return GroupSettings
+     */
+    public function setAllowWaitinglist(?string $allowWaitinglist): GroupSettings
+    {
+        $this->allowWaitinglist = $allowWaitinglist;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getWaitinglistMaxPersons(): ?string
+    {
+        return $this->waitinglistMaxPersons;
+    }
+
+    /**
+     * @param string|null $waitinglistMaxPersons
+     * @return GroupSettings
+     */
+    public function setWaitinglistMaxPersons(?string $waitinglistMaxPersons): GroupSettings
+    {
+        $this->waitinglistMaxPersons = $waitinglistMaxPersons;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getAutomaticMoveUp(): ?string
+    {
+        return $this->automaticMoveUp;
+    }
+
+    /**
+     * @param string|null $automaticMoveUp
+     * @return GroupSettings
+     */
+    public function setAutomaticMoveUp(?string $automaticMoveUp): GroupSettings
+    {
+        $this->automaticMoveUp = $automaticMoveUp;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getIsPublic(): ?string
+    {
+        return $this->isPublic;
+    }
+
+    /**
+     * @param string|null $isPublic
+     * @return GroupSettings
+     */
+    public function setIsPublic(?string $isPublic): GroupSettings
+    {
+        $this->isPublic = $isPublic;
+        return $this;
+    }
+
+    /**
+     * @return array
+     */
+    public function getGroupMeeting(): array
+    {
+        return $this->groupMeeting;
+    }
+
+    /**
+     * @param array $groupMeeting
+     * @return GroupSettings
+     */
+    public function setGroupMeeting(array $groupMeeting): GroupSettings
+    {
+        $this->groupMeeting = $groupMeeting;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getQrCodeCheckin(): ?string
+    {
+        return $this->qrCodeCheckin;
+    }
+
+    /**
+     * @param string|null $qrCodeCheckin
+     * @return GroupSettings
+     */
+    public function setQrCodeCheckin(?string $qrCodeCheckin): GroupSettings
+    {
+        $this->qrCodeCheckin = $qrCodeCheckin;
+        return $this;
+    }
+
+    /**
+     * @return array
+     */
+    public function getNewMember(): array
+    {
+        return $this->newMember;
+    }
+
+    /**
+     * @param array $newMember
+     * @return GroupSettings
+     */
+    public function setNewMember(array $newMember): GroupSettings
+    {
+        $this->newMember = $newMember;
+        return $this;
+    }
+}
\ No newline at end of file
diff --git a/src/Models/Person.php b/src/Models/Person.php
index 98922a9b..e0652861 100644
--- a/src/Models/Person.php
+++ b/src/Models/Person.php
@@ -7,6 +7,7 @@
 use CTApi\Models\Traits\FillWithData;
 use CTApi\Models\Traits\MetaAttribute;
 use CTApi\Requests\PersonEventRequestBuilder;
+use CTApi\Requests\PersonGroupRequestBuilder;
 
 class Person
 {
@@ -38,17 +39,44 @@ class Person
 
     protected ?Meta $meta = null;
 
+    protected function fillNonArrayType(string $key, $value)
+    {
+        switch ($key) {
+            case "domainIdentifier":
+                $this->setId($value);
+                break;
+            default:
+                $this->{$key} = $value;
+        }
+    }
+
     protected function fillArrayType(string $key, array $data): void
     {
         switch ($key) {
             case "meta":
                 $this->setMeta(Meta::createModelFromData($data));
                 break;
+            case "domainAttributes":
+                $this->processDomainAttributes($data);
+                break;
             default:
                 $this->{$key} = $data;
         }
     }
 
+    private function processDomainAttributes(array $domainAttributes)
+    {
+        if (array_key_exists('firstName', $domainAttributes)) {
+            $this->setFirstName($domainAttributes['firstName']);
+        }
+        if (array_key_exists('lastName', $domainAttributes)) {
+            $this->setLastName($domainAttributes['lastName']);
+        }
+        if (array_key_exists('guid', $domainAttributes)) {
+            $this->setGuid($domainAttributes['guid']);
+        }
+    }
+
     public function requestEvents(): ?PersonEventRequestBuilder
     {
         if (!is_null($this->getId())) {
@@ -57,6 +85,14 @@ public function requestEvents(): ?PersonEventRequestBuilder
         return null;
     }
 
+    public function requestGroups(): ?PersonGroupRequestBuilder
+    {
+        if (!is_null($this->getId())) {
+            return new PersonGroupRequestBuilder((int)$this->getId());
+        }
+        return null;
+    }
+
 
     /**
      * @return string|null
diff --git a/src/Models/PersonGroup.php b/src/Models/PersonGroup.php
new file mode 100644
index 00000000..d2d74e6e
--- /dev/null
+++ b/src/Models/PersonGroup.php
@@ -0,0 +1,92 @@
+<?php
+
+
+namespace CTApi\Models;
+
+
+use CTApi\Models\Traits\FillWithData;
+use CTApi\Requests\GroupRequest;
+
+class PersonGroup
+{
+    use FillWithData;
+
+    protected ?Group $group = null;
+    protected ?int $groupTypeRoleId = null;
+    protected ?string $memberStartDate = null;
+
+    protected function fillArrayType(string $key, array $data)
+    {
+        switch ($key) {
+            case "group":
+                $this->group = Group::createModelFromData($data);
+                break;
+            default:
+                $this->{$key} = $data;
+        }
+    }
+
+    public function requestGroup(): ?Group
+    {
+        $id = $this->getGroup()?->getId();
+        if ($id != null) {
+            return GroupRequest::find($id);
+        } else {
+            return null;
+        }
+    }
+
+    /**
+     * @return Group|null
+     */
+    public function getGroup(): ?Group
+    {
+        return $this->group;
+    }
+
+    /**
+     * @param Group|null $group
+     * @return PersonGroup
+     */
+    public function setGroup(?Group $group): PersonGroup
+    {
+        $this->group = $group;
+        return $this;
+    }
+
+    /**
+     * @return int|null
+     */
+    public function getGroupTypeRoleId(): ?int
+    {
+        return $this->groupTypeRoleId;
+    }
+
+    /**
+     * @param int|null $groupTypeRoleId
+     * @return PersonGroup
+     */
+    public function setGroupTypeRoleId(?int $groupTypeRoleId): PersonGroup
+    {
+        $this->groupTypeRoleId = $groupTypeRoleId;
+        return $this;
+    }
+
+    /**
+     * @return string|null
+     */
+    public function getMemberStartDate(): ?string
+    {
+        return $this->memberStartDate;
+    }
+
+    /**
+     * @param string|null $memberStartDate
+     * @return PersonGroup
+     */
+    public function setMemberStartDate(?string $memberStartDate): PersonGroup
+    {
+        $this->memberStartDate = $memberStartDate;
+        return $this;
+    }
+}
\ No newline at end of file
diff --git a/src/Models/SongArrangement.php b/src/Models/SongArrangement.php
index b3218b25..2c7da1ef 100644
--- a/src/Models/SongArrangement.php
+++ b/src/Models/SongArrangement.php
@@ -11,14 +11,14 @@ class SongArrangement
 {
     use FillWithData, MetaAttribute;
 
-    protected ?string $id;
-    protected ?string $name;
-    protected ?string $isDefault;
-    protected ?string $keyOfArrangement;
-    protected ?string $bpm;
-    protected ?string $beat;
-    protected ?string $duration;
-    protected ?string $note;
+    protected ?string $id = null;
+    protected ?string $name = null;
+    protected ?string $isDefault = null;
+    protected ?string $keyOfArrangement = null;
+    protected ?string $bpm = null;
+    protected ?string $beat = null;
+    protected ?string $duration = null;
+    protected ?string $note = null;
     protected array $links = [];
     protected array $files = [];
 
diff --git a/src/Models/SongCategory.php b/src/Models/SongCategory.php
index 1dd5d829..9d0e0a21 100644
--- a/src/Models/SongCategory.php
+++ b/src/Models/SongCategory.php
@@ -8,11 +8,11 @@
 
 class SongCategory
 {
-    protected ?string $id;
-    protected ?string $name;
-    protected ?string $nameTranslated;
-    protected ?string $sortKey;
-    protected ?string $campusId;
+    protected ?string $id = null;
+    protected ?string $name = null;
+    protected ?string $nameTranslated = null;
+    protected ?string $sortKey = null;
+    protected ?string $campusId = null;
 
     use FillWithData;
 
diff --git a/src/Requests/GroupMemberRequestBuilder.php b/src/Requests/GroupMemberRequestBuilder.php
new file mode 100644
index 00000000..a3600071
--- /dev/null
+++ b/src/Requests/GroupMemberRequestBuilder.php
@@ -0,0 +1,30 @@
+<?php
+
+
+namespace CTApi\Requests;
+
+
+use CTApi\Models\GroupMember;
+use CTApi\Requests\Traits\OrderByCondition;
+use CTApi\Requests\Traits\Pagination;
+
+class GroupMemberRequestBuilder
+{
+    use Pagination, OrderByCondition;
+
+    private int $groupId;
+
+    function __construct(int $groupId)
+    {
+        $this->groupId = $groupId;
+    }
+
+    public function get(): array
+    {
+        $data = $this->collectDataFromPages('/api/groups/' . $this->groupId . '/members');
+        $this->orderRawData($data);
+
+        return GroupMember::createModelsFromArray($data);
+    }
+
+}
\ No newline at end of file
diff --git a/src/Requests/GroupRequest.php b/src/Requests/GroupRequest.php
new file mode 100644
index 00000000..ef749ba7
--- /dev/null
+++ b/src/Requests/GroupRequest.php
@@ -0,0 +1,37 @@
+<?php
+
+
+namespace CTApi\Requests;
+
+
+use CTApi\Models\Event;
+use CTApi\Models\Group;
+
+class GroupRequest
+{
+    public static function all(): array
+    {
+        return (new GroupRequestBuilder())->all();
+    }
+
+    public static function where(string $key, $value): GroupRequestBuilder
+    {
+        return (new GroupRequestBuilder())->where($key, $value);
+    }
+
+    public static function orderBy(string $key, $orderAscending = true): GroupRequestBuilder
+    {
+        return (new GroupRequestBuilder())->orderBy($key, $orderAscending);
+    }
+
+    public static function findOrFail(int $id): Group
+    {
+        return (new GroupRequestBuilder())->findOrFail($id);
+    }
+
+    public static function find(int $id): ?Group
+    {
+        return (new GroupRequestBuilder())->find($id);
+    }
+
+}
\ No newline at end of file
diff --git a/src/Requests/GroupRequestBuilder.php b/src/Requests/GroupRequestBuilder.php
new file mode 100644
index 00000000..d1ebf001
--- /dev/null
+++ b/src/Requests/GroupRequestBuilder.php
@@ -0,0 +1,65 @@
+<?php
+
+
+namespace CTApi\Requests;
+
+
+use CTApi\CTClient;
+use CTApi\Exceptions\CTModelException;
+use CTApi\Models\Event;
+use CTApi\Models\Group;
+use CTApi\Requests\Traits\OrderByCondition;
+use CTApi\Requests\Traits\Pagination;
+use CTApi\Requests\Traits\WhereCondition;
+use CTApi\Utils\CTResponseUtil;
+use GuzzleHttp\Exception\GuzzleException;
+
+class GroupRequestBuilder
+{
+    use Pagination, WhereCondition, OrderByCondition;
+
+    public function all(): array
+    {
+        $data = $this->collectDataFromPages('/api/groups', []);
+        return Group::createModelsFromArray($data);
+    }
+
+    public function findOrFail(int $id): Group
+    {
+        $group = $this->find($id);
+        if($group != null){
+            return $group;
+        }else{
+            throw new CTModelException("Could not retrieve model!");
+        }
+    }
+
+    public function find(int $id): ?Group
+    {
+        $groupData = null;
+        try{
+            $response = CTClient::getClient()->get('/api/groups/'.$id);
+            $groupData = CTResponseUtil::dataAsArray($response);
+        } catch(GuzzleException $e){
+            // ignore
+        }
+
+        if(empty($groupData)){
+            return null;
+        } else {
+            return Group::createModelFromData($groupData);
+        }
+    }
+
+    public function get(): array
+    {
+        $options = [];
+        $this->addWhereConditionsToOption($options);
+
+        $data = $this->collectDataFromPages('/api/groups', $options);
+
+        $this->orderRawData($data);
+
+        return Event::createModelsFromArray($data);
+    }
+}
\ No newline at end of file
diff --git a/src/Requests/PersonGroupRequestBuilder.php b/src/Requests/PersonGroupRequestBuilder.php
new file mode 100644
index 00000000..9bd8a44b
--- /dev/null
+++ b/src/Requests/PersonGroupRequestBuilder.php
@@ -0,0 +1,32 @@
+<?php
+
+
+namespace CTApi\Requests;
+
+
+use CTApi\Models\Group;
+use CTApi\Models\PersonGroup;
+use CTApi\Requests\Traits\OrderByCondition;
+use CTApi\Requests\Traits\Pagination;
+use CTApi\Requests\Traits\WhereCondition;
+
+class PersonGroupRequestBuilder
+{
+    use Pagination, OrderByCondition;
+
+    private int $personId;
+
+    public function __construct(int $personId)
+    {
+        $this->personId = $personId;
+    }
+
+    public function get(): array
+    {
+        $data = $this->collectDataFromPages('/api/persons/' . $this->personId . '/groups');
+        $this->orderRawData($data);
+
+        return PersonGroup::createModelsFromArray($data);
+    }
+
+}
\ No newline at end of file
diff --git a/tests/integration/Requests/GroupMemberRequestTest.php b/tests/integration/Requests/GroupMemberRequestTest.php
new file mode 100644
index 00000000..0ded5753
--- /dev/null
+++ b/tests/integration/Requests/GroupMemberRequestTest.php
@@ -0,0 +1,54 @@
+<?php
+
+
+namespace Tests\Integration\Requests;
+
+
+use CTApi\Models\Group;
+use CTApi\Models\GroupMember;
+use CTApi\Models\Person;
+use CTApi\Requests\GroupRequest;
+use Tests\Integration\TestCaseAuthenticated;
+use Tests\Integration\TestData;
+
+class GroupMemberRequestTest extends TestCaseAuthenticated
+{
+
+    private string $groupId = "";
+    private string $groupName = "";
+
+    protected function setUp(): void
+    {
+        if (!TestData::getValue("GROUP_SHOULD_TEST") == "YES") {
+            $this->markTestSkipped("Test suite is disabled in testdata.ini");
+        } else {
+            $this->groupId = TestData::getValue("GROUP_ID") ?? "";
+            $this->groupName = TestData::getValue("GROUP_NAME") ?? "";
+        }
+    }
+
+    public function testGetGroupMembers()
+    {
+        $myGroup = GroupRequest::find((int)$this->groupId);
+        $this->assertNotNull($myGroup);
+        $this->assertInstanceOf(Group::class, $myGroup);
+
+        $firstMember = $myGroup->requestMembers()->get()[0];
+
+        $this->assertNotNull($firstMember->getPerson());
+        $this->assertInstanceOf(Person::class, $firstMember->getPerson());
+
+        $firstPerson = $firstMember->requestPerson();
+        $this->assertNotNull($firstPerson);
+        $this->assertInstanceOf(Person::class, $firstPerson);
+    }
+
+    public function testEmptyGroupMember()
+    {
+        $emptyGroupMember = GroupMember::createModelFromData([]);
+
+        $this->assertNull($emptyGroupMember->getPerson());
+        $this->assertNull($emptyGroupMember->requestPerson());
+    }
+
+}
\ No newline at end of file
diff --git a/tests/integration/Requests/GroupRequestTest.php b/tests/integration/Requests/GroupRequestTest.php
new file mode 100644
index 00000000..7a5bbb8b
--- /dev/null
+++ b/tests/integration/Requests/GroupRequestTest.php
@@ -0,0 +1,69 @@
+<?php
+
+
+namespace Tests\Integration\Requests;
+
+
+use CTApi\Models\Group;
+use CTApi\Models\GroupRole;
+use CTApi\Models\GroupSettings;
+use CTApi\Requests\GroupRequest;
+use Tests\Integration\TestCaseAuthenticated;
+use Tests\Integration\TestData;
+
+class GroupRequestTest extends TestCaseAuthenticated
+{
+
+    private string $groupId = "";
+    private string $groupName = "";
+
+    protected function setUp(): void
+    {
+        if (!TestData::getValue("GROUP_SHOULD_TEST") == "YES") {
+            $this->markTestSkipped("Test suite is disabled in testdata.ini");
+        } else {
+            $this->groupId = TestData::getValue("GROUP_ID") ?? "";
+            $this->groupName = TestData::getValue("GROUP_NAME") ?? "";
+        }
+    }
+
+    public function testGetAllGroups()
+    {
+        $allGroups = GroupRequest::all();
+
+        $this->assertIsArray($allGroups);
+        $foundMyGroup = false;
+        foreach ($allGroups as $group) {
+            $this->assertInstanceOf(Group::class, $group);
+            if ($group->getId() == $this->groupId) {
+                $foundMyGroup = true;
+            }
+        }
+        $this->assertTrue($foundMyGroup);
+    }
+
+    public function testGetGroup()
+    {
+        $myGroup = GroupRequest::find((int)$this->groupId);
+        $this->assertNotNull($myGroup);
+        $this->assertInstanceOf(Group::class, $myGroup);
+        $this->assertEquals($myGroup->getName(), $this->groupName);
+
+        $this->assertNotNull($myGroup->getRoles());
+        $this->assertNotEmpty($myGroup->getRoles());
+
+        $firstGroupRole = $myGroup->getRoles()[0];
+        $this->assertInstanceOf(GroupRole::class, $firstGroupRole);
+
+        $this->assertNotNull($myGroup->getSettings());
+        $this->assertInstanceOf(GroupSettings::class, $myGroup->getSettings());
+    }
+
+    public function testCreateEmptyGroup()
+    {
+        $myGroup = Group::createModelFromData([]);
+        $this->assertInstanceOf(Group::class, $myGroup);
+        $this->assertNull($myGroup->getId());
+    }
+
+}
\ No newline at end of file
diff --git a/tests/integration/Requests/PersonRequestTest.php b/tests/integration/Requests/PersonRequestTest.php
index 74b2173d..d1565bf4 100644
--- a/tests/integration/Requests/PersonRequestTest.php
+++ b/tests/integration/Requests/PersonRequestTest.php
@@ -3,7 +3,9 @@
 namespace Tests\Integration\Requests;
 
 use CTApi\Models\Event;
+use CTApi\Models\Group;
 use CTApi\Models\Person;
+use CTApi\Models\PersonGroup;
 use CTApi\Requests\AuthRequest;
 use CTApi\Requests\PersonRequest;
 use Exception;
@@ -88,6 +90,19 @@ public function testRequestEvents()
         foreach ($events as $event) {
             $this->assertInstanceOf(Event::class, $event);
         }
+    }
+
+    public function testRequestGroups()
+    {
+        $person = PersonRequest::whoami();
+
+        $groups = $person->requestGroups()->get();
 
+        $this->assertIsArray($groups);
+        foreach ($groups as $group) {
+            $this->assertInstanceOf(PersonGroup::class, $group);
+            $this->assertInstanceOf(Group::class, $group->getGroup());
+            $this->assertInstanceOf(Group::class, $group->requestGroup());
+        }
     }
 }
diff --git a/tests/integration/testdata.example.ini b/tests/integration/testdata.example.ini
index f87c7299..b6939ba0 100644
--- a/tests/integration/testdata.example.ini
+++ b/tests/integration/testdata.example.ini
@@ -47,4 +47,9 @@ WIKI_CATEGORY_ID = 21
 WIKI_CATEGORY_NAME = Tutorials
 WIKI_PAGE_IDENTIFIER = 289124-ion-209123-ioanwd-29012
 WIKI_PAGE_TITLE = How to add a CT-User
-WIKI_SEARCH_QUERY = user
\ No newline at end of file
+WIKI_SEARCH_QUERY = user
+
+# enable GROUP testsuite with YES and disable with NO
+GROUP_SHOULD_TEST = NO
+GROUP_ID = 291
+GROUP_NAME = Test Group
\ No newline at end of file