diff --git a/src/server.ts b/src/server.ts
index 71f7485..8822cbb 100644
--- a/src/server.ts
+++ b/src/server.ts
@@ -727,4 +727,20 @@ setInterval(() => {
 // Periodic persistence of dirty session states (every 5s)
 setInterval(persistDirtySessions, 5000);
 
+// Periodic cleanup for orphaned terminals (every 5 minutes)
+// Handles cases where session ended but WebSocket didn't close properly
+setInterval(
+  () => {
+    for (const [sessionId, termSession] of sessionTerminals.entries()) {
+      const session = getSession(sessionId);
+      if (session?.ended_at) {
+        console.debug(`Cleaning up orphaned terminal for session ${sessionId}`);
+        disposeTerminal(termSession);
+        sessionTerminals.delete(sessionId);
+      }
+    }
+  },
+  5 * 60 * 1000,
+);
+
 export { server };