diff --git a/notebook/notebookapp.py b/notebook/notebookapp.py
index 079b8716a6..6b680ed9a4 100755
--- a/notebook/notebookapp.py
+++ b/notebook/notebookapp.py
@@ -1739,7 +1739,7 @@ def launch_browser(self):
 
             # Write a temporary file to open in the browser
             fd, open_file = tempfile.mkstemp(suffix='.html')
-            with open(fd, 'w', encoding='utf-8') as fh:
+            with io.open(fd, 'w', encoding='utf-8') as fh:
                 self._write_browser_open_file(uri, fh)
         else:
             open_file = self.browser_open_file