diff --git a/ui/ozone/platform/x11/x11_window.cc b/ui/ozone/platform/x11/x11_window.cc
index 2459a05b3caad..6735172c2089b 100644
--- a/ui/ozone/platform/x11/x11_window.cc
+++ b/ui/ozone/platform/x11/x11_window.cc
@@ -2441,7 +2441,12 @@ void X11Window::OnWindowMapped() {
   // Some WMs only respect maximize hints after the window has been mapped.
   // Check whether we need to re-do a maximization.
   if (should_maximize_after_map_) {
+    // Maximize() may synchronously delete |this| via OnBoundsChanged.
+    auto weak_this = weak_ptr_factory_.GetWeakPtr();
     Maximize();
+    if (!weak_this) {
+      return;
+    }
     should_maximize_after_map_ = false;
   }
   if (should_grab_pointer_after_map_) {