diff --git a/src/xenia/ui/imgui_dialog.cc b/src/xenia/ui/imgui_dialog.cc
index ab8b06a85..20c9e0d0f 100644
--- a/src/xenia/ui/imgui_dialog.cc
+++ b/src/xenia/ui/imgui_dialog.cc
@@ -16,7 +16,7 @@
 namespace xe {
 namespace ui {
 
-uint64_t ImGuiDialog::next_window_id_ = 0;
+std::atomic<uint64_t> ImGuiDialog::next_window_id_ = 0;
 
 ImGuiDialog::ImGuiDialog(ImGuiDrawer* imgui_drawer)
     : imgui_drawer_(imgui_drawer) {
diff --git a/src/xenia/ui/imgui_dialog.h b/src/xenia/ui/imgui_dialog.h
index aefa2658c..c27a6572e 100644
--- a/src/xenia/ui/imgui_dialog.h
+++ b/src/xenia/ui/imgui_dialog.h
@@ -49,7 +49,7 @@ class ImGuiDialog {
   virtual void OnDraw(ImGuiIO& io) {}
 
  private:
-  static uint64_t next_window_id_;
+  static std::atomic<uint64_t> next_window_id_;
 
   ImGuiDrawer* imgui_drawer_ = nullptr;
   bool has_close_pending_ = false;