diff --git a/src/Item.php b/src/Item.php
index 7b6fcbb..eace119 100644
--- a/src/Item.php
+++ b/src/Item.php
@@ -130,26 +130,27 @@ public function getRelationships(): array
         $relationships = [];
 
         foreach ($this->getRelations() as $name => $relation) {
+            if (!$relation->hasIncluded()) {
+                continue;
+            }
+
             if ($relation instanceof OneRelationInterface) {
-                $relationships[$name] = ['data' => null];
+                $relationships[$name]['data'] = null;
 
                 if ($relation->getIncluded() !== null) {
-                    $relationships[$name] = [
-                        'data' => [
-                            'type' => $relation->getIncluded()->getType(),
-                            'id' => $relation->getIncluded()->getId(),
-                        ],
+                    $relationships[$name]['data'] = [
+                        'type' => $relation->getIncluded()->getType(),
+                        'id' => $relation->getIncluded()->getId(),
                     ];
                 }
             } elseif ($relation instanceof ManyRelationInterface) {
                 $relationships[$name]['data'] = [];
 
                 foreach ($relation->getIncluded() as $item) {
-                    $relationships[$name]['data'][] =
-                        [
-                            'type' => $item->getType(),
-                            'id' => $item->getId(),
-                        ];
+                    $relationships[$name]['data'][] = [
+                        'type' => $item->getType(),
+                        'id' => $item->getId(),
+                    ];
                 }
             }
         }
diff --git a/tests/ItemTest.php b/tests/ItemTest.php
index 7a69859..3c64648 100644
--- a/tests/ItemTest.php
+++ b/tests/ItemTest.php
@@ -119,6 +119,24 @@ public function is_adds_empty_hasone_relation_in_to_json_api_array()
         );
     }
 
+    /**
+     * @test
+     */
+    public function is_does_not_add_hasone_relation_without_data_in_to_json_api_array()
+    {
+        $item = new WithRelationshipItem();
+        $item->setId('1234');
+        $item->hasoneRelation();
+
+        $this->assertSame(
+            [
+                'type' => 'item-with-relationship',
+                'id' => '1234',
+            ],
+            $item->toJsonApiArray()
+        );
+    }
+
     /**
      * @test
      */
@@ -170,6 +188,24 @@ public function is_adds_empty_hasmany_relation_in_to_json_api_array()
         );
     }
 
+    /**
+     * @test
+     */
+    public function is_does_not_add_hasmany_relation_without_data_in_to_json_api_array()
+    {
+        $item = new WithRelationshipItem();
+        $item->setId('1234');
+        $item->hasmanyRelation();
+
+        $this->assertSame(
+            [
+                'type' => 'item-with-relationship',
+                'id' => '1234',
+            ],
+            $item->toJsonApiArray()
+        );
+    }
+
     /**
      * @test
      */
@@ -219,6 +255,24 @@ public function is_adds_empty_morphto_relation_in_to_json_api_array()
         );
     }
 
+    /**
+     * @test
+     */
+    public function is_does_not_add_morphto_relation_without_data_in_to_json_api_array()
+    {
+        $item = new WithRelationshipItem();
+        $item->setId('1234');
+        $item->morphtoRelation();
+
+        $this->assertSame(
+            [
+                'type' => 'item-with-relationship',
+                'id' => '1234',
+            ],
+            $item->toJsonApiArray()
+        );
+    }
+
     /**
      * @test
      */
@@ -270,6 +324,24 @@ public function is_adds_empty_morphtomany_relation_in_to_json_api_array()
         );
     }
 
+    /**
+     * @test
+     */
+    public function is_does_not_add_morphtomany_relation_without_data_in_to_json_api_array()
+    {
+        $item = new WithRelationshipItem();
+        $item->setId('1234');
+        $item->morphtomanyRelation();
+
+        $this->assertSame(
+            [
+                'type' => 'item-with-relationship',
+                'id' => '1234',
+            ],
+            $item->toJsonApiArray()
+        );
+    }
+
     /**
      * @test
      */