diff --git a/src/threads/thread.c b/src/threads/thread.c
index e587626..3e5d15c 100644
--- a/src/threads/thread.c
+++ b/src/threads/thread.c
@@ -383,7 +383,7 @@ thread_set_priority (int new_priority)
 
   thread_current ()->priority = new_priority;
 
-  if (new_priority < old_priority)
+  if (new_priority < old_priority && !list_empty (&ready_list))
     thread_yield ();
 }