diff --git a/tests/end2end/features/javascript.feature b/tests/end2end/features/javascript.feature
index e4b477e50..8fedf5af1 100644
--- a/tests/end2end/features/javascript.feature
+++ b/tests/end2end/features/javascript.feature
@@ -124,9 +124,9 @@ Feature: Javascript stuff
     # https://github.com/qutebrowser/qutebrowser/issues/1190
     # https://github.com/qutebrowser/qutebrowser/issues/2495
 
-    # Currently broken on Windows:
+    # Currently broken on Windows and on Qt 5.12
     # https://github.com/qutebrowser/qutebrowser/issues/4230
-    @posix
+    @posix @qt<5.12
     Scenario: Checking visible/invisible window size
         When I run :tab-only
         And I open data/javascript/windowsize.html in a new background tab
@@ -134,7 +134,7 @@ Feature: Javascript stuff
         And I run :tab-next
         Then the window sizes should be the same
 
-    @flaky
+    @flaky @qt<5.12
     Scenario: Checking visible/invisible window size with vertical tabbar
         When I run :tab-only
         And I set tabs.position to left
diff --git a/tests/unit/javascript/stylesheet/test_stylesheet.py b/tests/unit/javascript/stylesheet/test_stylesheet.py
index c58a0401d..145e8ee5e 100644
--- a/tests/unit/javascript/stylesheet/test_stylesheet.py
+++ b/tests/unit/javascript/stylesheet/test_stylesheet.py
@@ -128,8 +128,8 @@ def test_set_error(stylesheet_tester, config_stub):
     stylesheet_tester.check_set(GREEN_BODY_BG)
 
 
-@pytest.mark.xfail(qtutils.version_check('5.12', compiled=False),
-                   reason='Broken with Qt 5.12')
+@pytest.mark.skip(qtutils.version_check('5.12', compiled=False),
+                  reason='Broken with Qt 5.12')
 def test_appendchild(stylesheet_tester):
     stylesheet_tester.js.load('stylesheet/simple.html')
     stylesheet_tester.init_stylesheet()