diff --git a/Lib/idlelib/pyshell.py b/Lib/idlelib/pyshell.py
index ea49aff..11bafdb 100755
--- a/Lib/idlelib/pyshell.py
+++ b/Lib/idlelib/pyshell.py
@@ -1495,7 +1495,7 @@
     if system() == 'Windows':
         iconfile = os.path.join(icondir, 'idle.ico')
         root.wm_iconbitmap(default=iconfile)
-    else:
+    elif not macosx.isAquaTk():
         ext = '.png' if TkVersion >= 8.6 else '.gif'
         iconfiles = [os.path.join(icondir, 'idle_%d%s' % (size, ext))
                      for size in (16, 32, 48)]