diff --git a/qutebrowser/widgets/tabbedbrowser.py b/qutebrowser/widgets/tabbedbrowser.py
index e7ee0e850..5666f68a6 100644
--- a/qutebrowser/widgets/tabbedbrowser.py
+++ b/qutebrowser/widgets/tabbedbrowser.py
@@ -280,7 +280,8 @@ class TabbedBrowser(TabWidget):
         Return:
             The opened WebView instance.
         """
-        qt_ensure_valid(url)
+        if url is not None:
+            qt_ensure_valid(url)
         log.webview.debug("Creating new tab with URL {}".format(url))
         tab = WebView(self)
         self._connect_tab_signals(tab)