diff --git a/packages/app/src/app/agent/[serverId]/[agentId].tsx b/packages/app/src/app/agent/[serverId]/[agentId].tsx
index 77ec47dd0..4d6828ae1 100644
--- a/packages/app/src/app/agent/[serverId]/[agentId].tsx
+++ b/packages/app/src/app/agent/[serverId]/[agentId].tsx
@@ -153,6 +153,26 @@ function AgentScreenContent({ serverId, agentId, onBack }: AgentScreenContentPro
     resolvedAgentId ? state.sessions[serverId]?.agents?.get(resolvedAgentId) : undefined
   );
 
+  // Get parent agent ID for back navigation
+  const parentAgentId = agent?.parentAgentId;
+
+  // Navigate to parent agent if this is a child, otherwise go to homepage
+  const handleBack = useCallback(() => {
+    if (parentAgentId) {
+      // Child agent: navigate back to parent
+      router.push({
+        pathname: "/agent/[serverId]/[agentId]",
+        params: {
+          serverId: serverId,
+          agentId: parentAgentId,
+        },
+      });
+    } else {
+      // Root agent: navigate to homepage
+      onBack();
+    }
+  }, [parentAgentId, router, serverId, onBack]);
+
   // Select the agents Map directly - this is a stable reference that only changes when agents are added/removed
   const allAgents = useSessionStore((state) => state.sessions[serverId]?.agents);
 
@@ -507,7 +527,7 @@ function AgentScreenContent({ serverId, agentId, onBack }: AgentScreenContentPro
         {/* Header */}
         <BackHeader
           title={agent.title || "Agent"}
-          onBack={onBack}
+          onBack={handleBack}
           rightContent={
             <View ref={menuButtonRef} collapsable={false}>
               <Pressable onPress={handleOpenMenu} style={styles.menuButton}>
diff --git a/plan.md b/plan.md
index 05a64b539..71005cd67 100644
--- a/plan.md
+++ b/plan.md
@@ -697,13 +697,14 @@ interface ToolCallSheetData {
     4. ❌ Pressed back button (arrow icon in header) - navigated to **homepage** instead of parent agent screen
     **Root cause**: The `handleNavigateToChildAgent` in `[agentId].tsx` uses `router.push()` which adds to history, but the back button handler (`handleBack` at line ~202) uses `router.canGoBack() ? router.back() : router.push("/")` - this is working correctly for browser history. The issue is that when navigating from Sub-Agents menu, it closes the menu first and the navigation happens. The browser history should be: homepage → parent → child. But the navigation log shows `from: agent, to: home` suggesting the back action went directly to homepage. This may be due to router history being reset when the menu modal closes or a race condition.
 
-- [ ] **Fix**: Ensure back button returns to parent agent when navigating from sub-agent menu.
+- [x] **Fix**: Ensure back button returns to parent agent when navigating from sub-agent menu.
 
   - Investigate why router history shows `from: agent, to: home` instead of `from: child, to: parent`
   - The navigation from parent to child via Sub-Agents menu should properly add to browser history
   - Check if menu dismissal or modal closing is affecting router state
   - Test with `router.replace()` vs `router.push()` in `handleNavigateToChildAgent`
   - Ensure expo-router preserves navigation stack when navigating between agent screens
+  - **Done (2025-12-22 13:55)**: Fixed back navigation for child agents. The issue was that `BackHeader` always used the `onBack` prop which called `handleBackToHome` (always navigates to homepage). Added `handleBack` callback in `AgentScreenContent` that checks if the agent has a `parentAgentId` - if so, navigates to the parent agent screen; otherwise falls back to homepage navigation. Typecheck passes.
 
 - [ ] **Test**: Re-verify back button after fix.