diff --git a/enterprise/server/routes/org_models.py b/enterprise/server/routes/org_models.py
index 89362c3d46..ed2616d529 100644
--- a/enterprise/server/routes/org_models.py
+++ b/enterprise/server/routes/org_models.py
@@ -210,6 +210,10 @@ class OrgUpdate(BaseModel):
     """Request model for updating an organization."""
 
     # Basic organization information (any authenticated user can update)
+    name: Annotated[
+        str | None,
+        StringConstraints(strip_whitespace=True, min_length=1, max_length=255),
+    ] = None
     contact_name: str | None = None
     contact_email: EmailStr | None = None
     conversation_expiration: int | None = None
diff --git a/enterprise/server/routes/orgs.py b/enterprise/server/routes/orgs.py
index dd2e2af68c..fb04be5bed 100644
--- a/enterprise/server/routes/orgs.py
+++ b/enterprise/server/routes/orgs.py
@@ -449,6 +449,11 @@ async def update_org(
             status_code=status.HTTP_404_NOT_FOUND,
             detail=str(e),
         )
+    except OrgNameExistsError as e:
+        raise HTTPException(
+            status_code=status.HTTP_409_CONFLICT,
+            detail=str(e),
+        )
     except PermissionError as e:
         # User lacks permission for LLM settings
         raise HTTPException(
diff --git a/enterprise/storage/org_service.py b/enterprise/storage/org_service.py
index 1537607f94..144d636a83 100644
--- a/enterprise/storage/org_service.py
+++ b/enterprise/storage/org_service.py
@@ -521,6 +521,7 @@ class OrgService:
         Raises:
             ValueError: If organization not found
             PermissionError: If user is not a member, or lacks admin/owner role for LLM settings
+            OrgNameExistsError: If new name already exists for another organization
             OrgDatabaseError: If database update fails
         """
         logger.info(
@@ -550,6 +551,24 @@ class OrgService:
                 'User must be a member of the organization to update it'
             )
 
+        # Check if name is being updated and validate uniqueness
+        if update_data.name is not None:
+            # Check if new name conflicts with another org
+            existing_org_with_name = OrgStore.get_org_by_name(update_data.name)
+            if (
+                existing_org_with_name is not None
+                and existing_org_with_name.id != org_id
+            ):
+                logger.warning(
+                    'Attempted to update organization with duplicate name',
+                    extra={
+                        'user_id': user_id,
+                        'org_id': str(org_id),
+                        'attempted_name': update_data.name,
+                    },
+                )
+                raise OrgNameExistsError(update_data.name)
+
         # Check if update contains any LLM settings
         llm_fields_being_updated = OrgService._has_llm_settings_updates(update_data)
         if llm_fields_being_updated:
diff --git a/enterprise/tests/unit/server/routes/test_orgs.py b/enterprise/tests/unit/server/routes/test_orgs.py
index ccb6e67496..a57bea6378 100644
--- a/enterprise/tests/unit/server/routes/test_orgs.py
+++ b/enterprise/tests/unit/server/routes/test_orgs.py
@@ -1651,6 +1651,34 @@ async def test_update_org_permission_denied_llm_settings(mock_update_app):
             )
 
 
+@pytest.mark.asyncio
+async def test_update_org_duplicate_name_returns_409(mock_update_app):
+    """
+    GIVEN: User updates organization name to one already used by another org
+    WHEN: PATCH /api/organizations/{org_id} is called with that name
+    THEN: 409 Conflict is returned with message about name already existing
+    """
+    # Arrange
+    org_id = uuid.uuid4()
+    update_data = {'name': 'Existing Organization'}
+
+    with patch(
+        'server.routes.orgs.OrgService.update_org_with_permissions',
+        AsyncMock(side_effect=OrgNameExistsError('Existing Organization')),
+    ):
+        async with httpx.AsyncClient(
+            transport=httpx.ASGITransport(app=mock_update_app), base_url='http://test'
+        ) as client:
+            # Act
+            response = await client.patch(
+                f'/api/organizations/{org_id}', json=update_data
+            )
+
+            # Assert
+            assert response.status_code == status.HTTP_409_CONFLICT
+            assert 'already exists' in response.json()['detail'].lower()
+
+
 @pytest.mark.asyncio
 async def test_update_org_database_error(mock_update_app):
     """
@@ -1751,6 +1779,27 @@ async def test_update_org_invalid_field_values(mock_update_app):
         assert response.status_code == status.HTTP_422_UNPROCESSABLE_ENTITY
 
 
+@pytest.mark.asyncio
+async def test_update_org_empty_name_returns_422(mock_update_app):
+    """
+    GIVEN: Update request with empty organization name (after strip)
+    WHEN: PATCH /api/organizations/{org_id} is called
+    THEN: 422 validation error is returned (OrgUpdate name min_length=1)
+    """
+    # Arrange
+    org_id = uuid.uuid4()
+    update_data = {'name': '   '}
+
+    async with httpx.AsyncClient(
+        transport=httpx.ASGITransport(app=mock_update_app), base_url='http://test'
+    ) as client:
+        # Act
+        response = await client.patch(f'/api/organizations/{org_id}', json=update_data)
+
+        # Assert
+        assert response.status_code == status.HTTP_422_UNPROCESSABLE_ENTITY
+
+
 @pytest.mark.asyncio
 async def test_update_org_invalid_email_format(mock_update_app):
     """
diff --git a/enterprise/tests/unit/test_org_service.py b/enterprise/tests/unit/test_org_service.py
index 8e0438ba1d..31f96adfc8 100644
--- a/enterprise/tests/unit/test_org_service.py
+++ b/enterprise/tests/unit/test_org_service.py
@@ -1535,6 +1535,118 @@ async def test_update_org_with_permissions_database_error(session_maker):
         assert 'Failed to update organization' in str(exc_info.value)
 
 
+@pytest.mark.asyncio
+async def test_update_org_with_permissions_duplicate_name_raises_org_name_exists_error(
+    session_maker,
+):
+    """
+    GIVEN: User updates org name to a name already used by another organization
+    WHEN: update_org_with_permissions is called
+    THEN: OrgNameExistsError is raised with the conflicting name
+    """
+    # Arrange
+    org_id = uuid.uuid4()
+    other_org_id = uuid.uuid4()
+    user_id = str(uuid.uuid4())
+    duplicate_name = 'Existing Org Name'
+
+    mock_current_org = Org(
+        id=org_id,
+        name='My Org',
+        contact_name='John Doe',
+        contact_email='john@example.com',
+        org_version=5,
+    )
+    mock_org_with_name = Org(
+        id=other_org_id,
+        name=duplicate_name,
+        contact_name='Jane Doe',
+        contact_email='jane@example.com',
+    )
+
+    from server.routes.org_models import OrgUpdate
+
+    update_data = OrgUpdate(name=duplicate_name)
+
+    with (
+        patch('storage.org_store.session_maker', session_maker),
+        patch('storage.org_member_store.session_maker', session_maker),
+        patch('storage.role_store.session_maker', session_maker),
+        patch(
+            'storage.org_service.OrgStore.get_org_by_id',
+            return_value=mock_current_org,
+        ),
+        patch('storage.org_service.OrgService.is_org_member', return_value=True),
+        patch(
+            'storage.org_service.OrgStore.get_org_by_name',
+            return_value=mock_org_with_name,
+        ),
+    ):
+        # Act & Assert
+        with pytest.raises(OrgNameExistsError) as exc_info:
+            await OrgService.update_org_with_permissions(
+                org_id=org_id,
+                update_data=update_data,
+                user_id=user_id,
+            )
+
+        assert duplicate_name in str(exc_info.value)
+
+
+@pytest.mark.asyncio
+async def test_update_org_with_permissions_same_name_allowed(session_maker):
+    """
+    GIVEN: User updates org with name unchanged (same as current org name)
+    WHEN: update_org_with_permissions is called
+    THEN: No OrgNameExistsError; update proceeds (name uniqueness allows same org)
+    """
+    # Arrange
+    org_id = uuid.uuid4()
+    user_id = str(uuid.uuid4())
+    current_name = 'My Org'
+
+    mock_org = Org(
+        id=org_id,
+        name=current_name,
+        contact_name='John Doe',
+        contact_email='john@example.com',
+        org_version=5,
+    )
+
+    from server.routes.org_models import OrgUpdate
+
+    update_data = OrgUpdate(name=current_name)
+
+    with (
+        patch('storage.org_store.session_maker', session_maker),
+        patch('storage.org_member_store.session_maker', session_maker),
+        patch('storage.role_store.session_maker', session_maker),
+        patch(
+            'storage.org_service.OrgStore.get_org_by_id',
+            return_value=mock_org,
+        ),
+        patch('storage.org_service.OrgService.is_org_member', return_value=True),
+        patch(
+            'storage.org_service.OrgStore.get_org_by_name',
+            return_value=mock_org,
+        ),
+        patch(
+            'storage.org_service.OrgStore.update_org',
+            return_value=mock_org,
+        ),
+    ):
+        # Act
+        result = await OrgService.update_org_with_permissions(
+            org_id=org_id,
+            update_data=update_data,
+            user_id=user_id,
+        )
+
+        # Assert
+        assert result is not None
+        assert result.name == current_name
+
+
 @pytest.mark.asyncio
 async def test_update_org_with_permissions_only_llm_fields(session_maker):
     """