diff --git a/packages/backend-defaults/src/entrypoints/permissionsRegistry/permissionsRegistryServiceFactory.test.ts b/packages/backend-defaults/src/entrypoints/permissionsRegistry/permissionsRegistryServiceFactory.test.ts
new file mode 100644
index 0000000000..578c76378a
--- /dev/null
+++ b/packages/backend-defaults/src/entrypoints/permissionsRegistry/permissionsRegistryServiceFactory.test.ts
@@ -0,0 +1,82 @@
+/*
+ * Copyright 2022 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * 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 {
+  coreServices,
+  createBackendPlugin,
+} from '@backstage/backend-plugin-api';
+import { startTestBackend } from '@backstage/backend-test-utils';
+import { createPermissionResourceRef } from '@backstage/plugin-permission-node';
+import { permissionsRegistryServiceFactory } from './permissionsRegistryServiceFactory';
+
+describe('permissionsRegistryServiceFactory', () => {
+  it('should reject resource refs from other plugins', async () => {
+    await expect(
+      startTestBackend({
+        features: [
+          permissionsRegistryServiceFactory,
+          createBackendPlugin({
+            pluginId: 'test',
+            register(reg) {
+              reg.registerInit({
+                deps: { permissionsRegistry: coreServices.permissionsRegistry },
+                async init({ permissionsRegistry }) {
+                  permissionsRegistry.addResourceType({
+                    resourceRef: createPermissionResourceRef<
+                      unknown,
+                      unknown
+                    >().with({
+                      pluginId: 'other',
+                      resourceType: 'some-resource',
+                    }),
+                    rules: [],
+                  });
+                },
+              });
+            },
+          }),
+        ],
+      }),
+    ).rejects.toThrowErrorMatchingInlineSnapshot(
+      `"Plugin 'test' startup failed; caused by Error: Resource type 'some-resource' belongs to plugin 'other', but was used with plugin 'test'"`,
+    );
+
+    await expect(
+      startTestBackend({
+        features: [
+          permissionsRegistryServiceFactory,
+          createBackendPlugin({
+            pluginId: 'test',
+            register(reg) {
+              reg.registerInit({
+                deps: { permissionsRegistry: coreServices.permissionsRegistry },
+                async init({ permissionsRegistry }) {
+                  permissionsRegistry.getPermissionRuleset(
+                    createPermissionResourceRef<unknown, unknown>().with({
+                      pluginId: 'other',
+                      resourceType: 'some-resource',
+                    }),
+                  );
+                },
+              });
+            },
+          }),
+        ],
+      }),
+    ).rejects.toThrowErrorMatchingInlineSnapshot(
+      `"Plugin 'test' startup failed; caused by Error: Resource type 'some-resource' belongs to plugin 'other', but was used with plugin 'test'"`,
+    );
+  });
+});
diff --git a/packages/backend-defaults/src/entrypoints/permissionsRegistry/permissionsRegistryServiceFactory.ts b/packages/backend-defaults/src/entrypoints/permissionsRegistry/permissionsRegistryServiceFactory.ts
index 993fb4e946..7ff6eabf03 100644
--- a/packages/backend-defaults/src/entrypoints/permissionsRegistry/permissionsRegistryServiceFactory.ts
+++ b/packages/backend-defaults/src/entrypoints/permissionsRegistry/permissionsRegistryServiceFactory.ts
@@ -19,7 +19,18 @@ import {
   coreServices,
   createServiceFactory,
 } from '@backstage/backend-plugin-api';
-import { createPermissionIntegrationRouter } from '@backstage/plugin-permission-node';
+import {
+  PermissionResourceRef,
+  createPermissionIntegrationRouter,
+} from '@backstage/plugin-permission-node';
+
+function assertRefPluginId(ref: PermissionResourceRef, pluginId: string) {
+  if (ref.pluginId !== pluginId) {
+    throw new Error(
+      `Resource type '${ref.resourceType}' belongs to plugin '${ref.pluginId}', but was used with plugin '${pluginId}'`,
+    );
+  }
+}
 
 /**
  * Permission system integration for registering resources and permissions.
@@ -35,9 +46,11 @@ export const permissionsRegistryServiceFactory = createServiceFactory({
   deps: {
     lifecycle: coreServices.lifecycle,
     httpRouter: coreServices.httpRouter,
+    pluginMetadata: coreServices.pluginMetadata,
   },
-  async factory({ httpRouter, lifecycle }) {
+  async factory({ httpRouter, lifecycle, pluginMetadata }) {
     const router = createPermissionIntegrationRouter();
+    const pluginId = pluginMetadata.getId();
 
     httpRouter.use(router);
 
@@ -53,6 +66,7 @@ export const permissionsRegistryServiceFactory = createServiceFactory({
             'Cannot add permission resource types after the plugin has started',
           );
         }
+        assertRefPluginId(resource.resourceRef, pluginId);
         router.addResourceType({
           ...resource,
           resourceType: resource.resourceRef.resourceType,
@@ -75,6 +89,7 @@ export const permissionsRegistryServiceFactory = createServiceFactory({
         router.addPermissionRules(rules);
       },
       getPermissionRuleset(resourceRef) {
+        assertRefPluginId(resourceRef, pluginId);
         return router.getPermissionRuleset(resourceRef);
       },
     } satisfies PermissionsRegistryService;