diff --git a/src/App.vue b/src/App.vue
index db9aefc6f..2f4ced0bd 100644
--- a/src/App.vue
+++ b/src/App.vue
@@ -398,6 +398,23 @@
                   @update:model-value="onDictationLanguageChange"
                 />
               </div>
+              <button
+                class="sidebar-settings-row"
+                type="button"
+                :disabled="browserNotificationPermission === 'unsupported' || browserNotificationPermission === 'denied'"
+                :title="browserNotificationHelpText"
+                @click="onToggleBrowserNotifications"
+              >
+                <span class="sidebar-settings-label">{{ t('Browser notifications') }}</span>
+                <span class="sidebar-settings-notification-control">
+                  <span v-if="browserNotificationStatusText" class="sidebar-settings-value">{{ browserNotificationStatusText }}</span>
+                  <span
+                    class="sidebar-settings-toggle"
+                    :class="{ 'is-on': browserNotificationsEnabled }"
+                    aria-hidden="true"
+                  />
+                </span>
+              </button>
               <button class="sidebar-settings-row" type="button" aria-live="polite" @click="isTelegramConfigOpen = !isTelegramConfigOpen">
                 <span class="sidebar-settings-label">{{ t('Telegram') }}</span>
                 <span class="sidebar-settings-value">{{ telegramStatusText }}</span>
@@ -1199,6 +1216,8 @@ const {
   selectedModelId,
   selectedReasoningEffort,
   selectedSpeedMode,
+  browserNotificationsEnabled,
+  browserNotificationPermission,
   installedSkills,
   accountRateLimitSnapshots,
   messages,
@@ -1231,6 +1250,8 @@ const {
 
   setSelectedReasoningEffort,
   updateSelectedSpeedMode,
+  setBrowserNotificationsEnabled,
+  refreshBrowserNotificationPermission,
   respondToPendingServerRequest,
   renameProject,
   removeProject,
@@ -1334,6 +1355,7 @@ const DICTATION_LANGUAGE_KEY = 'codex-web-local.dictation-language.v1'
 
 const CHAT_WIDTH_KEY = 'codex-web-local.chat-width.v1'
 const MOBILE_RESUME_RELOAD_MIN_HIDDEN_MS = 400
+const THREAD_NOTIFICATION_CLICK_EVENT = 'codex-thread-notification-click'
 const sendWithEnter = ref(loadBoolPref(SEND_WITH_ENTER_KEY, true))
 const inProgressSendMode = ref<'steer' | 'queue'>(loadInProgressSendModePref())
 const darkMode = ref<'system' | 'light' | 'dark'>(loadDarkModePref())
@@ -1768,10 +1790,25 @@ const telegramStatusText = computed(() => {
   const error = telegramStatus.value.lastError ? `, ${t('error')}: ${telegramStatus.value.lastError}` : ''
   return `${base}, ${mapped}${error}`
 })
+const browserNotificationStatusText = computed(() => {
+  if (browserNotificationPermission.value === 'unsupported') return t('Unsupported')
+  if (browserNotificationPermission.value === 'denied') return t('Blocked')
+  if (browserNotificationsEnabled.value) return t('On')
+  return ''
+})
+const browserNotificationHelpText = computed(() => {
+  if (browserNotificationPermission.value === 'unsupported') return t('This browser does not support notifications.')
+  if (browserNotificationPermission.value === 'denied') return t('Notifications are blocked in browser settings.')
+  return browserNotificationsEnabled.value
+    ? t('Notify when background thread tasks finish or need action.')
+    : t('Enable notifications for completed tasks and pending chat actions.')
+})
 
 onMounted(() => {
+  refreshBrowserNotificationPermission()
   document.addEventListener('pointerdown', onDocumentPointerDown)
   window.addEventListener('keydown', onWindowKeyDown)
+  window.addEventListener(THREAD_NOTIFICATION_CLICK_EVENT, onThreadNotificationClick)
   document.addEventListener('visibilitychange', onDocumentVisibilityChange)
   window.addEventListener('pageshow', onWindowPageShow)
   window.addEventListener('focus', onWindowFocus)
@@ -1796,6 +1833,7 @@ onMounted(() => {
 onUnmounted(() => {
   document.removeEventListener('pointerdown', onDocumentPointerDown)
   window.removeEventListener('keydown', onWindowKeyDown)
+  window.removeEventListener(THREAD_NOTIFICATION_CLICK_EVENT, onThreadNotificationClick)
   document.removeEventListener('visibilitychange', onDocumentVisibilityChange)
   window.removeEventListener('pageshow', onWindowPageShow)
   window.removeEventListener('focus', onWindowFocus)
@@ -2760,6 +2798,7 @@ function onSettingsAreaClick(event: MouseEvent): void {
 
 function onDocumentVisibilityChange(): void {
   if (typeof document === 'undefined') return
+  refreshBrowserNotificationPermission()
   if (!isMobile.value) return
 
   if (document.visibilityState === 'hidden') {
@@ -2777,6 +2816,7 @@ function onWindowPageShow(event: PageTransitionEvent): void {
 }
 
 function onWindowFocus(): void {
+  refreshBrowserNotificationPermission()
   if (route.name === 'home') {
     void loadWorkspaceRootOptionsState()
     void refreshDefaultProjectName()
@@ -3758,6 +3798,10 @@ function onDictationLanguageChange(nextValue: string): void {
   window.localStorage.setItem(DICTATION_LANGUAGE_KEY, value)
 }
 
+function onToggleBrowserNotifications(): void {
+  void setBrowserNotificationsEnabled(!browserNotificationsEnabled.value)
+}
+
 function loadDictationLanguagePref(): string {
   if (typeof window === 'undefined') return 'auto'
   const value = window.localStorage.getItem(DICTATION_LANGUAGE_KEY)?.trim() || 'auto'
@@ -3885,6 +3929,23 @@ function threadExistsInSidebar(threadId: string): boolean {
   return projectGroups.value.some((group) => group.threads.some((thread) => thread.id === threadId))
 }
 
+function readThreadIdFromNotificationEvent(event: Event): string {
+  if (!(event instanceof CustomEvent)) return ''
+  const detail = event.detail
+  if (!detail || typeof detail !== 'object' || Array.isArray(detail)) return ''
+  const threadId = (detail as Record<string, unknown>).threadId
+  return typeof threadId === 'string' ? threadId.trim() : ''
+}
+
+function onThreadNotificationClick(event: Event): void {
+  const threadId = readThreadIdFromNotificationEvent(event)
+  if (!threadId) return
+  void (async () => {
+    await selectThread(threadId)
+    await router.replace({ name: 'thread', params: { threadId } })
+  })()
+}
+
 async function syncThreadSelectionWithRoute(): Promise<void> {
   if (isRouteSyncInProgress.value) {
     hasPendingRouteSync = true
@@ -5046,6 +5107,13 @@ async function loadWorktreeBranches(sourceCwd: string): Promise<void> {
   @apply text-xs text-zinc-500 bg-zinc-100 rounded px-1.5 py-0.5;
 }
 
+.sidebar-settings-notification-control {
+  @apply inline-flex items-center gap-2;
+}
+
+.sidebar-settings-row:disabled {
+  @apply cursor-not-allowed opacity-70;
+}
 
 .sidebar-settings-toggle {
   @apply relative w-9 h-5 rounded-full bg-zinc-300 transition-colors shrink-0;
diff --git a/src/composables/useDesktopState.ts b/src/composables/useDesktopState.ts
index e64bac2b2..e3ec2759f 100644
--- a/src/composables/useDesktopState.ts
+++ b/src/composables/useDesktopState.ts
@@ -92,8 +92,12 @@ const RECENT_THREAD_MESSAGE_LOAD_REUSE_MS = 2000
 const REASONING_EFFORT_OPTIONS: ReasoningEffort[] = ['none', 'minimal', 'low', 'medium', 'high', 'xhigh']
 const GLOBAL_SERVER_REQUEST_SCOPE = '__global__'
 const MODEL_FALLBACK_ID = 'gpt-5.4-mini'
+const BROWSER_NOTIFICATIONS_STORAGE_KEY = 'codex-web-local.browser-notifications-enabled.v1'
 export type ProjectSortMode = 'recent' | 'manual'
 
+type BrowserNotificationPermission = NotificationPermission | 'unsupported'
+const THREAD_NOTIFICATION_CLICK_EVENT = 'codex-thread-notification-click'
+
 function loadReadStateMap(): Record<string, string> {
   if (typeof window === 'undefined') return {}
 
@@ -130,6 +134,25 @@ function saveUnreadCutoffIso(cutoffIso: string): void {
   window.localStorage.setItem(UNREAD_CUTOFF_STORAGE_KEY, cutoffIso)
 }
 
+function hasBrowserNotificationSupport(): boolean {
+  return typeof window !== 'undefined' && 'Notification' in window
+}
+
+function readBrowserNotificationPermission(): BrowserNotificationPermission {
+  if (!hasBrowserNotificationSupport()) return 'unsupported'
+  return window.Notification.permission
+}
+
+function loadBrowserNotificationsEnabled(): boolean {
+  if (typeof window === 'undefined') return false
+  return window.localStorage.getItem(BROWSER_NOTIFICATIONS_STORAGE_KEY) === 'true'
+}
+
+function saveBrowserNotificationsEnabled(enabled: boolean): void {
+  if (typeof window === 'undefined') return
+  window.localStorage.setItem(BROWSER_NOTIFICATIONS_STORAGE_KEY, enabled ? 'true' : 'false')
+}
+
 function isThreadUpdatedAfterCutoff(updatedAtIso: string, cutoffIso: string): boolean {
   if (!updatedAtIso || !cutoffIso) return false
   const updatedAtMs = new Date(updatedAtIso).getTime()
@@ -1505,6 +1528,8 @@ export function useDesktopState() {
   const codexRateLimit = ref<UiRateLimitSnapshot | null>(null)
   const threadTokenUsageByThreadId = ref<Record<string, UiThreadTokenUsage>>(loadThreadTokenUsageMap())
   const terminalOpenByThreadId = ref<Record<string, boolean>>(loadThreadTerminalOpenMap())
+  const browserNotificationsEnabled = ref(loadBrowserNotificationsEnabled())
+  const browserNotificationPermission = ref<BrowserNotificationPermission>(readBrowserNotificationPermission())
 
   const threadTitleById = ref<Record<string, string>>({})
 
@@ -2083,6 +2108,65 @@ export function useDesktopState() {
     return requests.length > 0 ? 'response' : null
   }
 
+  function findThreadById(threadId: string): UiThread | null {
+    return flattenThreads(projectGroups.value).find((thread) => thread.id === threadId) ??
+      flattenThreads(sourceGroups.value).find((thread) => thread.id === threadId) ??
+      null
+  }
+
+  function threadNotificationTitle(threadId: string): string {
+    const thread = findThreadById(threadId)
+    return threadTitleById.value[threadId] || thread?.title || thread?.preview || 'Codex thread'
+  }
+
+  function shouldSkipThreadBrowserNotification(threadId: string): boolean {
+    if (!threadId || threadId === GLOBAL_SERVER_REQUEST_SCOPE) return false
+    return selectedThreadId.value === threadId && typeof document !== 'undefined' && document.visibilityState === 'visible'
+  }
+
+  function showBrowserNotification(title: string, options: NotificationOptions & { threadId?: string } = {}): void {
+    browserNotificationPermission.value = readBrowserNotificationPermission()
+    if (!browserNotificationsEnabled.value || browserNotificationPermission.value !== 'granted') return
+    if (!hasBrowserNotificationSupport()) return
+
+    const { threadId, ...notificationOptions } = options
+    try {
+      const notification = new window.Notification(title, {
+        icon: '/icons/pwa-192x192.png',
+        ...notificationOptions,
+      })
+      notification.onclick = () => {
+        window.focus()
+        if (threadId && threadId !== GLOBAL_SERVER_REQUEST_SCOPE) {
+          window.dispatchEvent(new CustomEvent(THREAD_NOTIFICATION_CLICK_EVENT, { detail: { threadId } }))
+        }
+        notification.close()
+      }
+    } catch {
+      // Browser notification construction can still fail after permission checks.
+    }
+  }
+
+  function notifyPendingServerRequest(request: UiServerRequest): void {
+    if (shouldSkipThreadBrowserNotification(request.threadId)) return
+    const isApproval = isApprovalRequestMethod(request.method)
+    const title = isApproval ? 'Codex needs approval' : 'Codex needs a response'
+    showBrowserNotification(title, {
+      body: threadNotificationTitle(request.threadId),
+      tag: `codex-pending-${request.threadId || GLOBAL_SERVER_REQUEST_SCOPE}-${isApproval ? 'approval' : 'response'}`,
+      threadId: request.threadId,
+    })
+  }
+
+  function notifyTurnCompleted(turn: TurnCompletedInfo): void {
+    if (shouldSkipThreadBrowserNotification(turn.threadId)) return
+    showBrowserNotification('Codex task complete', {
+      body: threadNotificationTitle(turn.threadId),
+      tag: `codex-complete-${turn.threadId}`,
+      threadId: turn.threadId,
+    })
+  }
+
   function applyThreadFlags(): void {
     const withTitles = applyCachedTitlesToGroups(sourceGroups.value)
     const flaggedGroups: UiProjectGroup[] = withTitles.map((group) => ({
@@ -3061,6 +3145,7 @@ export function useDesktopState() {
       const request = normalizeServerRequest(notification.params)
       if (!request) return true
       upsertPendingServerRequest(request)
+      notifyPendingServerRequest(request)
       return true
     }
 
@@ -3733,6 +3818,7 @@ export function useDesktopState() {
       if (!shouldRetryWithFallback) {
         clearPendingTurnRequest(completedTurn.threadId)
         scheduleQueueStateRefresh(completedTurn.threadId)
+        notifyTurnCompleted(completedTurn)
       }
     }
 
@@ -5499,6 +5585,38 @@ export function useDesktopState() {
     threadTokenUsageByThreadId.value = {}
   }
 
+  async function setBrowserNotificationsEnabled(enabled: boolean): Promise<void> {
+    if (!enabled) {
+      browserNotificationsEnabled.value = false
+      saveBrowserNotificationsEnabled(false)
+      browserNotificationPermission.value = readBrowserNotificationPermission()
+      return
+    }
+
+    browserNotificationPermission.value = readBrowserNotificationPermission()
+    if (browserNotificationPermission.value === 'unsupported' || browserNotificationPermission.value === 'denied') {
+      browserNotificationsEnabled.value = false
+      saveBrowserNotificationsEnabled(false)
+      return
+    }
+
+    if (browserNotificationPermission.value !== 'granted') {
+      browserNotificationPermission.value = await window.Notification.requestPermission()
+    }
+
+    const canEnable = browserNotificationPermission.value === 'granted'
+    browserNotificationsEnabled.value = canEnable
+    saveBrowserNotificationsEnabled(canEnable)
+  }
+
+  function refreshBrowserNotificationPermission(): void {
+    browserNotificationPermission.value = readBrowserNotificationPermission()
+    if (browserNotificationPermission.value !== 'granted' && browserNotificationsEnabled.value) {
+      browserNotificationsEnabled.value = false
+      saveBrowserNotificationsEnabled(false)
+    }
+  }
+
   const selectedThreadQueuedMessages = computed<QueuedMessage[]>(() => {
     const threadId = selectedThreadId.value
     if (!threadId) return []
@@ -5572,6 +5690,8 @@ export function useDesktopState() {
     selectedModelId,
     selectedReasoningEffort,
     selectedSpeedMode,
+    browserNotificationsEnabled,
+    browserNotificationPermission,
     installedSkills,
     accountRateLimitSnapshots,
     messages,
@@ -5610,6 +5730,8 @@ export function useDesktopState() {
 
     setSelectedReasoningEffort,
     updateSelectedSpeedMode,
+    setBrowserNotificationsEnabled,
+    refreshBrowserNotificationPermission,
     respondToPendingServerRequest,
     renameProject,
     removeProject,
diff --git a/tests.md b/tests.md
index 427b74175..f5b9bb6e8 100644
--- a/tests.md
+++ b/tests.md
@@ -4832,3 +4832,39 @@ The sidebar Chats section lists all projectless chats and no longer shows the pe
 
 #### Rollback/Cleanup
 - None.
+
+---
+
+### Browser notifications for completed and pending thread turns
+
+#### Feature/Change Name
+Browser notifications can be enabled for background thread completion and pending chat approvals or responses.
+
+#### Prerequisites/Setup
+1. Dev server running (`pnpm run dev`)
+2. Browser notification permission is not blocked for the dev server origin
+3. Light theme and dark theme both available from the appearance switcher
+
+#### Steps
+1. In light theme, open the sidebar settings menu.
+2. Click `Browser notifications` and grant the browser permission prompt.
+3. Confirm the row shows `On`.
+4. Start or open a thread, send a prompt that completes after a short delay, then switch to another thread or hide the browser tab before completion.
+5. Confirm a browser notification appears with `Codex task complete` and the thread title or preview.
+6. Start a turn that asks for approval or user input, then switch to another thread or hide the browser tab.
+7. Confirm a browser notification appears with either `Codex needs approval` or `Codex needs a response`.
+8. Click the notification and confirm the app focuses and selects the relevant thread.
+9. Return to settings, click `Browser notifications` again, and confirm notifications turn off.
+10. Switch to dark theme and repeat steps 1-3, confirming the setting row and status remain readable.
+
+#### Expected Results
+- Notifications are opt-in and persisted after permission is granted.
+- Completed background turns show a `Codex task complete` notification.
+- Pending approval and response requests show a user-action notification.
+- Notifications are suppressed for the currently visible selected thread.
+- Clicking a notification focuses the app and selects the related thread.
+- The settings control is readable in light theme and dark theme.
+
+#### Rollback/Cleanup
+- Turn off `Browser notifications` in sidebar settings.
+- If needed, reset browser notification permission for the dev server origin in browser site settings.