diff --git a/src/widgets/widgets/qgroupbox.cpp b/src/widgets/widgets/qgroupbox.cpp
index 69eac1ebf7..eec794562a 100644
--- a/src/widgets/widgets/qgroupbox.cpp
+++ b/src/widgets/widgets/qgroupbox.cpp
@@ -389,9 +389,13 @@ bool QGroupBox::event(QEvent *e)
 void QGroupBox::childEvent(QChildEvent *c)
 {
     Q_D(QGroupBox);
-    if (c->type() != QEvent::ChildAdded || !c->child()->isWidgetType())
+    /*
+        Children might have been enabled after being added to the group box, in which case
+        the childEvent handler ran too early, and we need to disabled children again.
+    */
+    if (!(c->added() || c->polished()) || !c->child()->isWidgetType())
         return;
-    QWidget *w = (QWidget*)c->child();
+    QWidget *w = static_cast<QWidget*>(c->child());
     if (w->isWindow())
         return;
     if (d->checkable) {
diff --git a/tests/auto/widgets/widgets/qgroupbox/tst_qgroupbox.cpp b/tests/auto/widgets/widgets/qgroupbox/tst_qgroupbox.cpp
index 420ef56106..1b477fbbd0 100644
--- a/tests/auto/widgets/widgets/qgroupbox/tst_qgroupbox.cpp
+++ b/tests/auto/widgets/widgets/qgroupbox/tst_qgroupbox.cpp
@@ -295,6 +295,12 @@ void tst_QGroupBox::enabledChildPropagation()
     QVERIFY(!childWidget->isEnabled());
     dialog = new QDialog(&testWidget);
     QVERIFY(dialog->isEnabled());
+
+    // children that are enabled after adding should still be disabled before
+    // they are shown
+    childWidget->setEnabled(true);
+    testWidget.show();
+    QVERIFY(!childWidget->isEnabled());
 }
 
 void tst_QGroupBox::sizeHint()