diff --git a/src/App.tsx b/src/App.tsx
index 9ce9b2c..6e35350 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -11,6 +11,7 @@ import { ToolCollapseProvider } from './contexts/ToolCollapseContext';
 import { sessionDisplayName } from './lib/sessionName';
 import { X } from 'lucide-react';
 import { useT } from './hooks/useLocale';
+import { useSwipeSidebar } from './hooks/useSwipeSidebar';
 
 const Chat = lazy(() => import('./components/Chat').then(m => ({ default: m.Chat })));
 
@@ -83,6 +84,7 @@ export default function App() {
 
   const [sidebarOpen, setSidebarOpen] = useState(false);
   const [shortcutsOpen, setShortcutsOpen] = useState(false);
+  useSwipeSidebar(sidebarOpen, () => setSidebarOpen(true), () => setSidebarOpen(false));
   const { notify, soundEnabled, toggleSound } = useNotifications();
   const prevMessageCountRef = useRef(messages.length);
 
diff --git a/src/hooks/useSwipeSidebar.ts b/src/hooks/useSwipeSidebar.ts
new file mode 100644
index 0000000..0b930c5
--- /dev/null
+++ b/src/hooks/useSwipeSidebar.ts
@@ -0,0 +1,81 @@
+import { useEffect, useRef, useCallback } from 'react';
+
+const EDGE_ZONE = 30; // px from left edge to start detecting
+const MIN_SWIPE = 50; // minimum px distance to trigger
+const MAX_Y_DRIFT = 80; // if vertical movement exceeds this, abort
+
+/**
+ * Swipe-to-open / swipe-to-close sidebar on touch devices.
+ * - Swipe right from the left edge → open
+ * - Swipe left anywhere when open → close
+ */
+export function useSwipeSidebar(
+  isOpen: boolean,
+  onOpen: () => void,
+  onClose: () => void,
+) {
+  const touchStart = useRef<{ x: number; y: number; time: number } | null>(null);
+  const isSwipingRef = useRef(false);
+
+  const handleTouchStart = useCallback((e: TouchEvent) => {
+    const touch = e.touches[0];
+    if (!touch) return;
+
+    // When closed: only detect from left edge
+    // When open: detect anywhere (to close)
+    if (!isOpen && touch.clientX > EDGE_ZONE) return;
+
+    touchStart.current = { x: touch.clientX, y: touch.clientY, time: Date.now() };
+    isSwipingRef.current = false;
+  }, [isOpen]);
+
+  const handleTouchMove = useCallback((e: TouchEvent) => {
+    if (!touchStart.current) return;
+    const touch = e.touches[0];
+    if (!touch) return;
+
+    const dx = touch.clientX - touchStart.current.x;
+    const dy = Math.abs(touch.clientY - touchStart.current.y);
+
+    // Too much vertical drift → not a horizontal swipe
+    if (dy > MAX_Y_DRIFT) {
+      touchStart.current = null;
+      return;
+    }
+
+    if (Math.abs(dx) > 10) {
+      isSwipingRef.current = true;
+    }
+  }, []);
+
+  const handleTouchEnd = useCallback((e: TouchEvent) => {
+    if (!touchStart.current) return;
+    const touch = e.changedTouches[0];
+    if (!touch) { touchStart.current = null; return; }
+
+    const dx = touch.clientX - touchStart.current.x;
+    const dy = Math.abs(touch.clientY - touchStart.current.y);
+    const elapsed = Date.now() - touchStart.current.time;
+    touchStart.current = null;
+
+    // Only act on horizontal swipes
+    if (dy > MAX_Y_DRIFT || elapsed > 500) return;
+
+    if (!isOpen && dx > MIN_SWIPE) {
+      onOpen();
+    } else if (isOpen && dx < -MIN_SWIPE) {
+      onClose();
+    }
+  }, [isOpen, onOpen, onClose]);
+
+  useEffect(() => {
+    document.addEventListener('touchstart', handleTouchStart, { passive: true });
+    document.addEventListener('touchmove', handleTouchMove, { passive: true });
+    document.addEventListener('touchend', handleTouchEnd, { passive: true });
+    return () => {
+      document.removeEventListener('touchstart', handleTouchStart);
+      document.removeEventListener('touchmove', handleTouchMove);
+      document.removeEventListener('touchend', handleTouchEnd);
+    };
+  }, [handleTouchStart, handleTouchMove, handleTouchEnd]);
+}