diff --git a/.changeset/grumpy-experts-leave.md b/.changeset/grumpy-experts-leave.md
new file mode 100644
index 0000000000..7504fe6428
--- /dev/null
+++ b/.changeset/grumpy-experts-leave.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-app': patch
+---
+
+Fixed a regression that caused disabled nav items to appear in the navigation bar.
diff --git a/plugins/app/src/extensions/AppNav.test.tsx b/plugins/app/src/extensions/AppNav.test.tsx
new file mode 100644
index 0000000000..387c75a87a
--- /dev/null
+++ b/plugins/app/src/extensions/AppNav.test.tsx
@@ -0,0 +1,100 @@
+/*
+ * Copyright 2026 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 { screen, waitFor, within } from '@testing-library/react';
+import { renderTestApp } from '@backstage/frontend-test-utils';
+import {
+  PageBlueprint,
+  NavItemBlueprint,
+  createRouteRef,
+} from '@backstage/frontend-plugin-api';
+
+const DEFAULT_CONFIG = {
+  app: { baseUrl: 'http://localhost:3000' },
+  backend: { baseUrl: 'http://localhost:7007' },
+};
+
+const mockPage = PageBlueprint.make({
+  name: 'my-plugin',
+  params: {
+    title: 'My Plugin',
+    icon: <span>icon</span>,
+    path: '/my-plugin',
+    routeRef: createRouteRef(),
+  },
+});
+
+const mockNavItem = NavItemBlueprint.make({
+  name: 'my-plugin',
+  params: {
+    title: 'My Plugin',
+    icon: () => <span>icon</span>,
+    routeRef: createRouteRef(),
+  },
+});
+
+describe('AppNav', () => {
+  it('should show a nav item for a page with an enabled nav-item extension', async () => {
+    renderTestApp({
+      extensions: [mockPage, mockNavItem],
+      config: DEFAULT_CONFIG,
+    });
+
+    await waitFor(() => {
+      expect(
+        within(screen.getByRole('navigation')).getByText('My Plugin'),
+      ).toBeInTheDocument();
+    });
+  });
+
+  it('should hide a nav item when its nav-item extension is disabled via config', async () => {
+    renderTestApp({
+      extensions: [mockPage, mockNavItem],
+      config: {
+        ...DEFAULT_CONFIG,
+        app: {
+          ...DEFAULT_CONFIG.app,
+          extensions: [{ 'nav-item:test/my-plugin': false }],
+        },
+      },
+    });
+
+    await waitFor(() => {
+      expect(
+        within(screen.getByRole('navigation')).queryByText('My Plugin'),
+      ).not.toBeInTheDocument();
+    });
+  });
+
+  it('should still show a nav item for a page without a nav-item extension', async () => {
+    renderTestApp({
+      extensions: [mockPage],
+      config: {
+        ...DEFAULT_CONFIG,
+        app: {
+          ...DEFAULT_CONFIG.app,
+          extensions: [{ 'nav-item:test/my-plugin': false }],
+        },
+      },
+    });
+
+    await waitFor(() => {
+      expect(
+        within(screen.getByRole('navigation')).getByText('My Plugin'),
+      ).toBeInTheDocument();
+    });
+  });
+});
diff --git a/plugins/app/src/extensions/AppNav.tsx b/plugins/app/src/extensions/AppNav.tsx
index 09203303e5..0d6618fc8c 100644
--- a/plugins/app/src/extensions/AppNav.tsx
+++ b/plugins/app/src/extensions/AppNav.tsx
@@ -188,6 +188,14 @@ function NavContentRenderer(props: {
         return [];
       }
 
+      // TODO: Nav items are deprecated, and this code covers for a documented ability to use nav items still in config to disable pages in the sidebar.
+      // Remove this code once nav items are completely gone from the codebase.
+      const navItemNodeId = node.spec.id.replace(/^page:/, 'nav-item:');
+      const navItemNode = tree.nodes.get(navItemNodeId);
+      if (navItemNode?.spec.disabled) {
+        return [];
+      }
+
       const routeRef = node.instance.getData(coreExtensionData.routeRef);
       if (!routeRef) {
         return [];