diff --git a/Lib/lib-tk/tkCommonDialog.py b/Lib/lib-tk/tkCommonDialog.py
index c63ca11b68c..55cf0646cb1 100644
--- a/Lib/lib-tk/tkCommonDialog.py
+++ b/Lib/lib-tk/tkCommonDialog.py
@@ -27,6 +27,8 @@ class Dialog:
 
         self.master  = master
         self.options = options
+        if not master and options.get('parent'):
+            self.master = options['parent']
 
     def _fixoptions(self):
         pass # hook