diff --git a/chrome/browser/ui/views/frame/browser_view.cc b/chrome/browser/ui/views/frame/browser_view.cc
index c5b196b2be317..6d7aef1cdfbb1 100644
--- a/chrome/browser/ui/views/frame/browser_view.cc
+++ b/chrome/browser/ui/views/frame/browser_view.cc
@@ -1593,7 +1593,16 @@ void BrowserView::SetBounds(const gfx::Rect& bounds) {
     return;
   }
 
+  // ExitFullscreen() reaches Widget::SetFullscreen(), which on some platforms
+  // (macOS -[NSWindow toggleFullScreen:] nested run loop, Windows ::SetWindowPos
+  // synchronous WM dispatch) can run a deferred close and synchronously destroy
+  // `this`. See the matching guards in widget.cc:Widget::SetFullscreen and
+  // native_widget_ns_window_bridge.mm:FullscreenControllerToggleFullscreen.
+  auto weak_this = weak_ptr_factory_.GetWeakPtr();
   exclusive_access_context_->ExitFullscreen();
+  if (!weak_this) {
+    return;
+  }
 
   // If the BrowserFrameView has been created, give it a chance to handle the
   // BrowserWidget's bounds change.