diff --git a/joy/gui/textwidget.py b/joy/gui/textwidget.py
index b100602..8bb25fd 100644
--- a/joy/gui/textwidget.py
+++ b/joy/gui/textwidget.py
@@ -123,7 +123,7 @@ class SavingMixin(object):
   def _saver(self, text):
     if not self.filename:
       return
-    with open(self.filename, 'w') as f:
+    with open(self.filename, 'wb') as f:
       os.chmod(self.filename, 0o600)
       f.write(text.encode('UTF_8'))
       f.flush()