diff --git a/src/plugins/platforms/cocoa/qcocoawindow.mm b/src/plugins/platforms/cocoa/qcocoawindow.mm
index e350d7db51..2415e165dc 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.mm
+++ b/src/plugins/platforms/cocoa/qcocoawindow.mm
@@ -522,6 +522,8 @@ NSUInteger QCocoaWindow::windowStyleMask(Qt::WindowFlags flags)
             styleMask |= NSClosableWindowMask;
         if (flags & Qt::WindowMinimizeButtonHint)
             styleMask |= NSMiniaturizableWindowMask;
+        if (flags & Qt::WindowMaximizeButtonHint)
+            styleMask |= NSResizableWindowMask;
     } else {
         styleMask |= NSClosableWindowMask | NSTitledWindowMask;