diff --git a/Lib/idlelib/WindowList.py b/Lib/idlelib/WindowList.py
index 7e05a57c032..542b738674f 100644
--- a/Lib/idlelib/WindowList.py
+++ b/Lib/idlelib/WindowList.py
@@ -67,6 +67,10 @@ def __init__(self, master, **kw):
     def destroy(self):
         registry.delete(self)
         Toplevel.destroy(self)
+        # If this is Idle's last window then quit the mainloop
+        # (Needed for clean exit on Windows 98)
+        if not registry.dict:
+            self.quit()
 
     def get_title(self):
         # Subclass can override