diff --git a/.changeset/quiet-devices-sign-out.md b/.changeset/quiet-devices-sign-out.md
new file mode 100644
index 00000000000..5ca2bb395f6
--- /dev/null
+++ b/.changeset/quiet-devices-sign-out.md
@@ -0,0 +1,6 @@
+---
+'@clerk/shared': patch
+'@clerk/mosaic': patch
+---
+
+Fix cached active device sessions remaining after sign-out when the UserProfile device section has already been closed.
diff --git a/packages/mosaic/src/features/user-profile/user-profile-active-devices-section/__tests__/user-profile-active-devices-section.feature.test.tsx b/packages/mosaic/src/features/user-profile/user-profile-active-devices-section/__tests__/user-profile-active-devices-section.feature.test.tsx
index da0ef7e1f9c..8c0afe8da1e 100644
--- a/packages/mosaic/src/features/user-profile/user-profile-active-devices-section/__tests__/user-profile-active-devices-section.feature.test.tsx
+++ b/packages/mosaic/src/features/user-profile/user-profile-active-devices-section/__tests__/user-profile-active-devices-section.feature.test.tsx
@@ -217,21 +217,32 @@ describe('Active devices', () => {
     }
   });
 
-  it('drops cached devices on sign out', async () => {
+  it.each(['mounted', 'unmounted'] as const)('drops cached devices on sign out when %s', async state => {
     serveDevices([device('sess_current', 'active')]);
     const view = await renderWithClerk(<UserProfileActiveDevicesSection />);
     expect(await screen.findByText('This device')).toBeVisible();
+    const queryClient = getClerkQueryClient();
     const cachedDevices = () =>
-      getClerkQueryClient()
+      queryClient
         ?.getQueryCache()
         .getAll()
         .filter(query => query.state.data !== undefined) ?? [];
     expect(cachedDevices()).toHaveLength(1);
+    const cachedKeys = cachedDevices().map(query => query.queryKey);
+
+    if (state === 'unmounted') {
+      view.unmount();
+      expect(cachedDevices()).toHaveLength(1);
+    }
 
     await act(() => view.clerk.signOut());
 
     expect(view.container).toBeEmptyDOMElement();
+    expect(getClerkQueryClient()).toBe(queryClient);
     expect(cachedDevices()).toHaveLength(0);
+    for (const queryKey of cachedKeys) {
+      expect(queryClient?.getQueryCache().find({ queryKey, exact: true })).toBeUndefined();
+    }
   });
 
   it('shows signed-in sessions and signs out another device inside the security panel', async () => {
diff --git a/packages/mosaic/src/queries/use-user-sessions-query.ts b/packages/mosaic/src/queries/use-user-sessions-query.ts
index d8ce6e20c46..295852d52a9 100644
--- a/packages/mosaic/src/queries/use-user-sessions-query.ts
+++ b/packages/mosaic/src/queries/use-user-sessions-query.ts
@@ -1,7 +1,7 @@
 import {
   __internal_createCacheKeys,
-  __internal_useClearQueriesOnSignOut,
   __internal_useClerkQuery,
+  __internal_usePersistentQueryCleanupOnSignOut,
   useSession,
   useUser,
 } from '@clerk/shared/react';
@@ -15,7 +15,7 @@ export function useUserSessionsQuery() {
   const userId = user?.id;
   const sessionId = session?.id;
 
-  const { queryKey, stableKey, authenticated } = useMemo(
+  const { queryKey, stableKey } = useMemo(
     () =>
       __internal_createCacheKeys({
         stablePrefix: USER_SESSIONS_KEY,
@@ -26,12 +26,7 @@ export function useUserSessionsQuery() {
     [userId, sessionId],
   );
 
-  // Only runs while this hook is mounted, matching the shared hooks. Sign-out after unmount leaves the entry until it is garbage collected.
-  __internal_useClearQueriesOnSignOut({
-    isSignedOut: user === null,
-    authenticated,
-    stableKeys: stableKey,
-  });
+  __internal_usePersistentQueryCleanupOnSignOut(stableKey);
 
   return __internal_useClerkQuery({
     queryKey,
diff --git a/packages/shared/src/react/hooks/__tests__/usePersistentQueryCleanupOnSignOut.spec.ts b/packages/shared/src/react/hooks/__tests__/usePersistentQueryCleanupOnSignOut.spec.ts
new file mode 100644
index 00000000000..20232052a61
--- /dev/null
+++ b/packages/shared/src/react/hooks/__tests__/usePersistentQueryCleanupOnSignOut.spec.ts
@@ -0,0 +1,44 @@
+import { renderHook } from '@testing-library/react';
+import { StrictMode } from 'react';
+import { afterEach, expect, it, vi } from 'vitest';
+
+import type { Clerk, Resources } from '@/types';
+
+import { __createClerkTestQueryClient, __resetClerkQueryClientForTest } from '../../query/clerk-query-client';
+import { usePersistentQueryCleanupOnSignOut } from '../useClearQueriesOnSignOut';
+
+const { useClerkInstanceContext } = vi.hoisted(() => ({
+  useClerkInstanceContext: vi.fn<() => Pick<Clerk, 'addListener' | 'user'>>(),
+}));
+
+vi.mock('../../contexts', () => ({ useClerkInstanceContext }));
+
+afterEach(() => {
+  __resetClerkQueryClientForTest();
+  vi.clearAllMocks();
+});
+
+it('keeps one sign-out subscription after StrictMode setup and unmount', () => {
+  const client = __createClerkTestQueryClient();
+  const unsubscribe = vi.fn();
+  const clerk = {
+    user: undefined,
+    addListener: vi.fn<Clerk['addListener']>(() => unsubscribe),
+  };
+  useClerkInstanceContext.mockReturnValue(clerk);
+  client.setQueryData(['sessions', true], 'private');
+
+  const { unmount } = renderHook(() => usePersistentQueryCleanupOnSignOut('sessions'), { wrapper: StrictMode });
+  unmount();
+
+  expect(clerk.addListener).toHaveBeenCalledTimes(1);
+  expect(unsubscribe).not.toHaveBeenCalled();
+  const callback = clerk.addListener.mock.calls[0]?.[0];
+  callback?.({
+    user: null,
+    get client(): Resources['client'] {
+      throw new Error('Sign-out cleanup must not read the client resource');
+    },
+  });
+  expect(client.getQueryState(['sessions', true])).toBeUndefined();
+});
diff --git a/packages/shared/src/react/hooks/index.ts b/packages/shared/src/react/hooks/index.ts
index 700275614d8..26b85f3027c 100644
--- a/packages/shared/src/react/hooks/index.ts
+++ b/packages/shared/src/react/hooks/index.ts
@@ -83,7 +83,10 @@ export type {
 } from './useOrganizationSSOBypassAllowlist';
 
 export { createCacheKeys as __internal_createCacheKeys } from './createCacheKeys';
-export { useClearQueriesOnSignOut as __internal_useClearQueriesOnSignOut } from './useClearQueriesOnSignOut';
+export {
+  useClearQueriesOnSignOut as __internal_useClearQueriesOnSignOut,
+  usePersistentQueryCleanupOnSignOut as __internal_usePersistentQueryCleanupOnSignOut,
+} from './useClearQueriesOnSignOut';
 export { useClerkQuery as __internal_useClerkQuery } from '../query/useQuery';
 
 export { useUserBase as __internal_useUserBase } from './base/useUserBase';
diff --git a/packages/shared/src/react/hooks/useClearQueriesOnSignOut.ts b/packages/shared/src/react/hooks/useClearQueriesOnSignOut.ts
index 25ae0847e34..e9b969c7f2d 100644
--- a/packages/shared/src/react/hooks/useClearQueriesOnSignOut.ts
+++ b/packages/shared/src/react/hooks/useClearQueriesOnSignOut.ts
@@ -1,5 +1,7 @@
 import { useEffect, useRef } from 'react';
 
+import { useClerkInstanceContext } from '../contexts';
+import { registerQueryCleanupOnSignOut } from '../query/clerk-query-client';
 import { useClerkQueryClient } from '../query/use-clerk-query-client';
 import { usePreviousValue } from './usePreviousValue';
 
@@ -59,3 +61,14 @@ export function useClearQueriesOnSignOut(options: ClearQueriesOnSignOutOptions)
     }
   }, [authenticated, isSignedOut, previousIsSignedIn, queryClient]);
 }
+
+export function usePersistentQueryCleanupOnSignOut(stableKey: string): void {
+  const clerk = useClerkInstanceContext();
+  const [queryClient, isLoaded] = useClerkQueryClient();
+
+  useEffect(() => {
+    if (isLoaded) {
+      registerQueryCleanupOnSignOut(clerk, stableKey);
+    }
+  }, [clerk, isLoaded, queryClient, stableKey]);
+}
diff --git a/packages/shared/src/react/query/__tests__/clerk-query-client.spec.ts b/packages/shared/src/react/query/__tests__/clerk-query-client.spec.ts
index 0d3e8eba0ad..8a32899445f 100644
--- a/packages/shared/src/react/query/__tests__/clerk-query-client.spec.ts
+++ b/packages/shared/src/react/query/__tests__/clerk-query-client.spec.ts
@@ -1,11 +1,15 @@
 import { QueryClient } from '@tanstack/query-core';
 import { afterEach, describe, expect, it, vi } from 'vitest';
 
+import type { Clerk, Resources } from '@/types';
+import { createDeferredPromise } from '@/utils/createDeferredPromise';
+
 import {
   __createClerkTestQueryClient,
   __resetClerkQueryClientForTest,
   __setClerkQueryClientForTest,
   getClerkQueryClient,
+  registerQueryCleanupOnSignOut,
 } from '../clerk-query-client';
 
 afterEach(() => {
@@ -82,3 +86,144 @@ describe('__createClerkTestQueryClient', () => {
     expect(defaults?.refetchOnMount).toBe(false);
   });
 });
+
+function resources(user: Clerk['user']): Resources {
+  return {
+    user,
+    get client(): Resources['client'] {
+      throw new Error('Sign-out cleanup must not read the client resource');
+    },
+  };
+}
+
+function createClerkListener(user: Clerk['user'] = undefined) {
+  const listeners = new Set<Parameters<Clerk['addListener']>[0]>();
+  const unsubscribe = vi.fn();
+  const clerk = {
+    user,
+    addListener: vi.fn<Clerk['addListener']>(callback => {
+      listeners.add(callback);
+      callback(resources(clerk.user));
+      return () => {
+        listeners.delete(callback);
+        unsubscribe();
+      };
+    }),
+  };
+  return {
+    clerk,
+    unsubscribe,
+    emit(user: Clerk['user']) {
+      clerk.user = user;
+      listeners.forEach(callback => callback(resources(user)));
+    },
+  };
+}
+
+describe('registerQueryCleanupOnSignOut', () => {
+  it('clears registered authenticated queries on null but ignores unresolved user state', () => {
+    const client = __createClerkTestQueryClient();
+    const { clerk, emit } = createClerkListener();
+    client.setQueryData(['sessions', true], 'private');
+    client.setQueryData(['sessions', false], 'public');
+    client.setQueryData(['billing', true], 'unrelated');
+
+    registerQueryCleanupOnSignOut(clerk, 'sessions');
+    emit(undefined);
+    expect(client.getQueryData(['sessions', true])).toBe('private');
+
+    emit(null);
+    expect(client.getQueryState(['sessions', true])).toBeUndefined();
+    expect(client.getQueryData(['sessions', false])).toBe('public');
+    expect(client.getQueryData(['billing', true])).toBe('unrelated');
+  });
+
+  it('clears stale entries on initial null and when another prefix registers after sign-out', () => {
+    const client = __createClerkTestQueryClient();
+    const { clerk } = createClerkListener(null);
+    client.setQueryData(['sessions', true], 'private');
+    client.setQueryData(['other-sessions', true], 'private');
+
+    registerQueryCleanupOnSignOut(clerk, 'sessions');
+    expect(client.getQueryState(['sessions', true])).toBeUndefined();
+
+    registerQueryCleanupOnSignOut(clerk, 'other-sessions');
+    expect(client.getQueryState(['other-sessions', true])).toBeUndefined();
+    expect(clerk.addListener).toHaveBeenCalledTimes(1);
+  });
+
+  it('registers one listener across repeated registrations and clears every registered prefix', () => {
+    const client = __createClerkTestQueryClient();
+    const { clerk, emit } = createClerkListener();
+    registerQueryCleanupOnSignOut(clerk, 'sessions');
+    registerQueryCleanupOnSignOut(clerk, 'sessions');
+    registerQueryCleanupOnSignOut(clerk, 'other-sessions');
+    client.setQueryData(['sessions', true], 'private');
+    client.setQueryData(['other-sessions', true], 'private');
+
+    emit(null);
+
+    expect(clerk.addListener).toHaveBeenCalledTimes(1);
+    expect(client.getQueryCache().getAll()).toHaveLength(0);
+  });
+
+  it('moves the subscription to a replacement Clerk while retaining registered prefixes', () => {
+    const client = __createClerkTestQueryClient();
+    const old = createClerkListener();
+    const next = createClerkListener();
+    registerQueryCleanupOnSignOut(old.clerk, 'sessions');
+    registerQueryCleanupOnSignOut(next.clerk, 'other-sessions');
+    client.setQueryData(['sessions', true], 'private');
+    client.setQueryData(['other-sessions', true], 'private');
+
+    old.emit(null);
+    expect(old.unsubscribe).toHaveBeenCalledTimes(1);
+    expect(client.getQueryCache().getAll()).toHaveLength(2);
+
+    next.emit(null);
+    expect(client.getQueryCache().getAll()).toHaveLength(0);
+  });
+
+  it.each(['reset', 'replace'] as const)('unsubscribes when the query client is %s', action => {
+    const original = __createClerkTestQueryClient();
+    const { clerk, unsubscribe } = createClerkListener();
+    registerQueryCleanupOnSignOut(clerk, 'sessions');
+    const callback = clerk.addListener.mock.calls[0]?.[0];
+    if (action === 'reset') {
+      __resetClerkQueryClientForTest();
+    }
+    const next = __createClerkTestQueryClient();
+    next.setQueryData(['sessions', true], 'new session');
+    callback?.(resources(null));
+
+    expect(unsubscribe).toHaveBeenCalledTimes(1);
+    expect(next.getQueryData(['sessions', true])).toBe('new session');
+    expect(next).not.toBe(original);
+  });
+
+  it('does not subscribe without a real query client', () => {
+    __setClerkQueryClientForTest(undefined);
+    const { clerk } = createClerkListener();
+
+    registerQueryCleanupOnSignOut(clerk, 'sessions');
+
+    expect(clerk.addListener).not.toHaveBeenCalled();
+  });
+
+  it('does not restore a removed entry when an in-flight request resolves', async () => {
+    const client = __createClerkTestQueryClient();
+    const { clerk, emit } = createClerkListener();
+    registerQueryCleanupOnSignOut(clerk, 'sessions');
+    const deferred = createDeferredPromise();
+    const pending = client.fetchQuery({ queryKey: ['sessions', true], queryFn: () => deferred.promise });
+    const settled = pending.catch(() => undefined);
+
+    emit(null);
+    expect(client.getQueryState(['sessions', true])).toBeUndefined();
+    deferred.resolve('stale sessions');
+    await settled;
+    await deferred.promise;
+
+    expect(client.getQueryState(['sessions', true])).toBeUndefined();
+  });
+});
diff --git a/packages/shared/src/react/query/clerk-query-client.ts b/packages/shared/src/react/query/clerk-query-client.ts
index bb155d005f4..fd5b6e05211 100644
--- a/packages/shared/src/react/query/clerk-query-client.ts
+++ b/packages/shared/src/react/query/clerk-query-client.ts
@@ -1,5 +1,7 @@
 import { QueryClient } from '@tanstack/query-core';
 
+import type { Clerk } from '../../types';
+
 /**
  * The QueryClient backing every clerk-query hook. Owned by `@clerk/shared` so the
  * `QueryObserver` that observes it and the `Query` objects inside it always
@@ -12,6 +14,53 @@ import { QueryClient } from '@tanstack/query-core';
 let clerkQueryClient: QueryClient | undefined;
 let initialized = false;
 
+type SignOutSubscription = {
+  clerk: Pick<Clerk, 'addListener' | 'user'>;
+  stableKeys: Set<string>;
+  unsubscribe: () => void;
+};
+
+let signOutSubscription: SignOutSubscription | undefined;
+
+function disposeSignOutSubscription(): void {
+  signOutSubscription?.unsubscribe();
+  signOutSubscription = undefined;
+}
+
+function removeAuthenticatedQueries(client: QueryClient, stableKeys: Set<string>): void {
+  client.removeQueries({
+    predicate: query => {
+      const [stableKey, authenticated] = query.queryKey;
+      return authenticated === true && typeof stableKey === 'string' && stableKeys.has(stableKey);
+    },
+  });
+}
+
+export function registerQueryCleanupOnSignOut(clerk: SignOutSubscription['clerk'], stableKey: string): void {
+  const client = getClerkQueryClient();
+  if (!client) {
+    return;
+  }
+
+  const stableKeys = signOutSubscription?.stableKeys ?? new Set<string>();
+  stableKeys.add(stableKey);
+
+  if (signOutSubscription?.clerk === clerk) {
+    if (clerk.user === null) {
+      removeAuthenticatedQueries(client, stableKeys);
+    }
+    return;
+  }
+
+  disposeSignOutSubscription();
+  const unsubscribe = clerk.addListener(({ user }) => {
+    if (user === null) {
+      removeAuthenticatedQueries(client, stableKeys);
+    }
+  });
+  signOutSubscription = { clerk, stableKeys, unsubscribe };
+}
+
 export function getClerkQueryClient(): QueryClient | undefined {
   if (typeof window === 'undefined') {
     return undefined;
@@ -29,6 +78,7 @@ export function getClerkQueryClient(): QueryClient | undefined {
  * state without triggering lazy creation on subsequent reads.
  */
 export function __setClerkQueryClientForTest(client: QueryClient | undefined): void {
+  disposeSignOutSubscription();
   clerkQueryClient = client;
   initialized = true;
 }
@@ -61,6 +111,7 @@ export function __createClerkTestQueryClient(): QueryClient {
  * next read lazy-creates a fresh client.
  */
 export function __resetClerkQueryClientForTest(): void {
+  disposeSignOutSubscription();
   clerkQueryClient = undefined;
   initialized = false;
 }