diff --git a/qutebrowser/mainwindow/tabbedbrowser.py b/qutebrowser/mainwindow/tabbedbrowser.py
index 22ad7dd6b..b01c9d282 100644
--- a/qutebrowser/mainwindow/tabbedbrowser.py
+++ b/qutebrowser/mainwindow/tabbedbrowser.py
@@ -433,8 +433,12 @@ class TabbedBrowser(tabwidget.TabWidget):
             # Make sure the background tab has the correct initial size.
             # With a foreground tab, it's going to be resized correctly by the
             # layout anyways.
-            tab_size = QSize(self.width(),
-                             self.height() - self.tabBar().height())
+            if self.tabBar().vertical:
+                tab_size = QSize(self.width() - self.tabBar().width(),
+                                 self.height())
+            else:
+                tab_size = QSize(self.width(),
+                                 self.height() - self.tabBar().height())
             tab.resize(tab_size)
             self.tab_index_changed.emit(self.currentIndex(), self.count())
         else:
diff --git a/tests/end2end/features/javascript.feature b/tests/end2end/features/javascript.feature
index efdd692ac..c6c7acc15 100644
--- a/tests/end2end/features/javascript.feature
+++ b/tests/end2end/features/javascript.feature
@@ -116,3 +116,12 @@ Feature: Javascript stuff
         And I wait for "[*/data/javascript/windowsize.html:*] loaded" in the log
         And I run :tab-next
         Then the window sizes should be the same
+
+    Scenario: Checking visible/invisible window size with vertical tabbar
+        When I run :tab-only
+        And I set general -> log-javascript-console to info
+        And I set tabs -> position to left
+        And I open data/javascript/windowsize.html in a new background tab
+        And I wait for "[*/data/javascript/windowsize.html:*] loaded" in the log
+        And I run :tab-next
+        Then the window sizes should be the same