diff --git a/packages/app-desktop/ElectronAppWrapper.ts b/packages/app-desktop/ElectronAppWrapper.ts
index bda4b36a0f..788adefba8 100644
--- a/packages/app-desktop/ElectronAppWrapper.ts
+++ b/packages/app-desktop/ElectronAppWrapper.ts
@@ -6,7 +6,7 @@ const shim: typeof ShimType = require('@joplin/lib/shim').default;
 import { isCallbackUrl } from '@joplin/lib/callbackUrlUtils';
 import { FileLocker } from '@joplin/utils/fs';
 import { IpcMessageHandler, IpcServer, Message, newHttpError, sendMessage, SendMessageOptions, startServer, stopServer } from '@joplin/utils/ipc';
-import { BrowserWindow, Tray, WebContents, screen, App, nativeTheme } from 'electron';
+import { BrowserWindow, Tray, WebContents, screen, App, nativeTheme, powerMonitor } from 'electron';
 import bridge from './bridge';
 import * as url from 'url';
 const path = require('path');
@@ -401,6 +401,15 @@ export default class ElectronAppWrapper {
 		};
 		addWindowEventHandlers(this.win_.webContents);
 
+		// BrowserWindow 'focus' fires when the OS gives focus to the application window
+		// (i.e. coming from another app or from the taskbar), not on intra-app focus switches.
+		// We use a dedicated IPC channel so the renderer can trigger an immediate sync on
+		// OS-level focus gain without conflating it with the 'window-focused' channel that
+		// handles Joplin-internal window routing.
+		this.win_.on('focus', () => {
+			this.win_?.webContents.send('main-window-focused');
+		});
+
 		// eslint-disable-next-line @typescript-eslint/no-explicit-any -- Old code before rule was applied
 		this.win_.on('close', (event: any) => {
 			// If it's on macOS, the app is completely closed only if the user chooses to close the app (willQuitApp_ will be true)
@@ -892,6 +901,11 @@ export default class ElectronAppWrapper {
 			event.preventDefault();
 			void this.openCallbackUrl(url);
 		});
+
+		// When the OS wakes from sleep, notify the renderer so it can trigger an immediate sync.
+		powerMonitor.on('resume', () => {
+			this.win_?.webContents.send('system-resumed');
+		});
 	}
 
 	public async openCallbackUrl(url: string) {
diff --git a/packages/app-desktop/app.ts b/packages/app-desktop/app.ts
index bdbb02ad32..1fb66e9e13 100644
--- a/packages/app-desktop/app.ts
+++ b/packages/app-desktop/app.ts
@@ -733,6 +733,23 @@ class Application extends BaseApplication {
 					});
 				}
 			});
+
+			// Trigger an immediate sync when the main window gains OS-level focus (i.e. the user
+			// switches back to Joplin from another application) or when the system wakes from sleep.
+			// A 30-second cool-down prevents duplicate syncs during rapid focus-in/focus-out cycles.
+			const minResumeSyncIntervalMs = 30_000;
+			let lastFocusSyncTime = 0;
+
+			const scheduleResumeSync = () => {
+				const now = Date.now();
+				if (now - lastFocusSyncTime > minResumeSyncIntervalMs) {
+					lastFocusSyncTime = now;
+					void reg.scheduleSync(0);
+				}
+			};
+
+			ipcRenderer.on('main-window-focused', scheduleResumeSync);
+			ipcRenderer.on('system-resumed', scheduleResumeSync);
 		});
 
 		addTask('app/initPluginService', () => this.initPluginService());
diff --git a/packages/app-mobile/root.tsx b/packages/app-mobile/root.tsx
index 6d99c7cb5d..dfd1d1dcf2 100644
--- a/packages/app-mobile/root.tsx
+++ b/packages/app-mobile/root.tsx
@@ -19,7 +19,7 @@ import SyncTargetJoplinServer from '@joplin/lib/SyncTargetJoplinServer';
 import SyncTargetJoplinCloud from '@joplin/lib/SyncTargetJoplinCloud';
 import SyncTargetOneDrive from '@joplin/lib/SyncTargetOneDrive';
 import { Keyboard, BackHandler, Animated, StatusBar, Platform, Dimensions } from 'react-native';
-import { AppState as RNAppState, EmitterSubscription, View, Text, Linking, NativeEventSubscription, Appearance, ActivityIndicator } from 'react-native';
+import { AppState as RNAppState, AppStateStatus, EmitterSubscription, View, Text, Linking, NativeEventSubscription, Appearance, ActivityIndicator } from 'react-native';
 import getResponsiveValue from './components/getResponsiveValue';
 import NetInfo, { NetInfoSubscription } from '@react-native-community/netinfo';
 const DropdownAlert = require('react-native-dropdownalert').default;
@@ -295,7 +295,8 @@ class AppComponent extends React.Component<AppComponentProps, AppComponentState>
 	private unsubscribeScreenWidthChangeHandler_: EmitterSubscription|undefined;
 	private unsubscribeNetInfoHandler_: NetInfoSubscription|undefined;
 	private unsubscribeNewShareListener_: UnsubscribeShareListener|undefined;
-	private onAppStateChange_: ()=> void;
+	private onAppStateChange_: (nextAppState: AppStateStatus)=> void;
+	private lastResumeSyncTime_ = 0;
 	private backButtonHandler_: BackButtonHandler;
 	private handleNewShare_: ()=> void;
 	private handleOpenURL_: (event: unknown)=> void;
@@ -315,8 +316,24 @@ class AppComponent extends React.Component<AppComponentProps, AppComponentState>
 			return this.backButtonHandler();
 		};
 
-		this.onAppStateChange_ = () => {
+		this.onAppStateChange_ = (nextAppState: AppStateStatus) => {
 			PoorManIntervals.update();
+
+			// Trigger sync immediately when the app becomes active (resume from background/lock screen).
+			// Only run when the app becomes active, with a 30-second minimum interval
+			// prevent sync spam on rapid lock/unlock cycles.
+			const minResumeSyncIntervalMs = 30_000;
+			if (nextAppState === 'active') {
+				const elapsed = Date.now() - this.lastResumeSyncTime_;
+				if (elapsed >= minResumeSyncIntervalMs) {
+					logger.info(`onAppStateChange_: App became active - scheduling immediate sync (elapsed since last resume sync: ${elapsed}ms)`);
+					this.lastResumeSyncTime_ = Date.now();
+
+					void reg.scheduleSync(0, null, true);
+				} else {
+					logger.info(`onAppStateChange_: App became active but skipping sync - minimum interval not reached (${elapsed}ms < ${minResumeSyncIntervalMs}ms)`);
+				}
+			}
 		};
 
 		// eslint-disable-next-line @typescript-eslint/no-explicit-any -- Old code before rule was applied