diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6a8d380918..ad4faf2bf0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,7 +18,7 @@ These are the section headers that we use:
 
 ### Added
 
-- Added `GET /api/v1/users/{user_id}/workspaces` endpoint to list the workspaces to which a user belongs ([#3308](https://github.com/argilla-io/argilla/pull/3308)).
+- Added `GET /api/v1/users/{user_id}/workspaces` endpoint to list the workspaces to which a user belongs ([#3308](https://github.com/argilla-io/argilla/pull/3308) and [#3343](https://github.com/argilla-io/argilla/pull/3343)).
 - Added `HuggingFaceDatasetMixIn` for internal usage, to detach the `FeedbackDataset` integrations from the class itself, and use MixIns instead ([#3326](https://github.com/argilla-io/argilla/pull/3326)).
 - Added `GET /api/v1/records/{record_id}/suggestions` API endpoint to get the list of suggestions for the responses associated to a record ([#3304](https://github.com/argilla-io/argilla/pull/3304)).
 - Added `POST /api/v1/records/{record_id}/suggestions` API endpoint to create a suggestion for a response associated to a record ([#3304](https://github.com/argilla-io/argilla/pull/3304)).
diff --git a/src/argilla/server/apis/v1/handlers/users.py b/src/argilla/server/apis/v1/handlers/users.py
index 81f7fac258..1bf5428f23 100644
--- a/src/argilla/server/apis/v1/handlers/users.py
+++ b/src/argilla/server/apis/v1/handlers/users.py
@@ -14,12 +14,12 @@
 
 from uuid import UUID
 
-from fastapi import APIRouter, Depends, Security
+from fastapi import APIRouter, Depends, HTTPException, Security, status
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from argilla.server.contexts import accounts
 from argilla.server.database import get_async_db
-from argilla.server.models import User
+from argilla.server.models import User, UserRole
 from argilla.server.policies import UserPolicyV1, authorize
 from argilla.server.schemas.v1.workspaces import Workspaces
 from argilla.server.security import auth
@@ -35,5 +35,17 @@ async def list_user_workspaces(
     current_user: User = Security(auth.get_current_user),
 ):
     await authorize(current_user, UserPolicyV1.list_workspaces)
-    workspaces = await accounts.list_workspaces_by_user_id(db, user_id)
+
+    user = await accounts.get_user_by_id(db, user_id)
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=f"User with id `{user_id}` not found",
+        )
+
+    if user.is_owner:
+        workspaces = await accounts.list_workspaces(db)
+    else:
+        workspaces = await accounts.list_workspaces_by_user_id(db, user_id)
+
     return Workspaces(items=workspaces)
diff --git a/src/argilla/server/contexts/accounts.py b/src/argilla/server/contexts/accounts.py
index 0b93d9ebb2..f77db8a9a6 100644
--- a/src/argilla/server/contexts/accounts.py
+++ b/src/argilla/server/contexts/accounts.py
@@ -94,7 +94,7 @@ async def delete_workspace(db: "AsyncSession", workspace: Workspace):
     return workspace
 
 
-async def get_user_by_id(db: Session, user_id: UUID) -> Union[User, None]:
+async def get_user_by_id(db: "AsyncSession", user_id: UUID) -> Union[User, None]:
     return await db.get(User, user_id)
 
 
diff --git a/tests/server/api/v1/test_users.py b/tests/server/api/v1/test_users.py
index 1a67dc5e72..2c822ca19c 100644
--- a/tests/server/api/v1/test_users.py
+++ b/tests/server/api/v1/test_users.py
@@ -11,12 +11,12 @@
 #  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
-
+import uuid
 from typing import TYPE_CHECKING
 
 import pytest
 from argilla._constants import API_KEY_HEADER_NAME
-from argilla.server.models import UserRole
+from argilla.server.models import User, UserRole
 
 from tests.factories import UserFactory, WorkspaceFactory
 
@@ -45,6 +45,24 @@ async def test_list_user_workspaces(self, client: "TestClient", owner_auth_heade
             ]
         }
 
+    async def test_list_user_workspaces_for_owner(self, client: "TestClient"):
+        workspaces = await WorkspaceFactory.create_batch(5)
+        owner = await UserFactory.create(role=UserRole.owner)
+
+        response = client.get(f"/api/v1/users/{owner.id}/workspaces", headers={API_KEY_HEADER_NAME: owner.api_key})
+        assert response.status_code == 200
+        assert response.json() == {
+            "items": [
+                {
+                    "id": str(workspace.id),
+                    "name": workspace.name,
+                    "inserted_at": workspace.inserted_at.isoformat(),
+                    "updated_at": workspace.updated_at.isoformat(),
+                }
+                for workspace in workspaces
+            ]
+        }
+
     @pytest.mark.parametrize("role", [UserRole.annotator, UserRole.admin])
     async def test_list_user_workspaces_as_restricted_user(self, client: "TestClient", role: UserRole):
         workspaces = await WorkspaceFactory.create_batch(3)
@@ -56,3 +74,7 @@ async def test_list_user_workspaces_as_restricted_user(self, client: "TestClient
         )
 
         assert response.status_code == 403
+
+    async def test_list_user_for_non_existing_user(self, client: "TestClient", owner_auth_header: dict):
+        response = client.get(f"/api/v1/users/{uuid.uuid4()}/workspaces", headers=owner_auth_header)
+        assert response.status_code == 404