diff --git a/src/threads/thread.c b/src/threads/thread.c
index 0a66d65..e34d23e 100644
--- a/src/threads/thread.c
+++ b/src/threads/thread.c
@@ -336,8 +336,11 @@ thread_yield (void)
   ASSERT (!intr_context ());
 
   old_level = intr_disable ();
+
+  /* Insert the thread back into the ready list in priority order. */
   if (cur != idle_thread) 
-    list_push_back (&ready_list, &cur->elem);
+    list_insert_ordered(&ready_list, &cur->elem, priority_more, NULL);
+
   cur->status = THREAD_READY;
   schedule ();
   intr_set_level (old_level);