diff --git a/crates/gpui/src/platform/test/window.rs b/crates/gpui/src/platform/test/window.rs
index 8894350edc..ea1edf5a91 100644
--- a/crates/gpui/src/platform/test/window.rs
+++ b/crates/gpui/src/platform/test/window.rs
@@ -33,8 +33,10 @@ pub(crate) struct TestWindowState {
     hover_status_change_callback: Option<Box<dyn FnMut(bool)>>,
     resize_callback: Option<Box<dyn FnMut(Size<Pixels>, f32)>>,
     moved_callback: Option<Box<dyn FnMut()>>,
+    appearance_change_callback: Option<Box<dyn FnMut()>>,
     input_handler: Option<PlatformInputHandler>,
     is_fullscreen: bool,
+    appearance: WindowAppearance,
 }
 
 #[derive(Clone)]
@@ -85,8 +87,10 @@ impl TestWindow {
             hover_status_change_callback: None,
             resize_callback: None,
             moved_callback: None,
+            appearance_change_callback: None,
             input_handler: None,
             is_fullscreen: false,
+            appearance: WindowAppearance::Light,
         })))
     }
 
@@ -113,6 +117,17 @@ impl TestWindow {
         self.0.lock().active_status_change_callback = Some(callback);
     }
 
+    pub fn simulate_appearance_change(&self, appearance: WindowAppearance) {
+        let mut lock = self.0.lock();
+        lock.appearance = appearance;
+        let Some(mut callback) = lock.appearance_change_callback.take() else {
+            return;
+        };
+        drop(lock);
+        callback();
+        self.0.lock().appearance_change_callback = Some(callback);
+    }
+
     pub fn simulate_input(&mut self, event: PlatformInput) -> bool {
         let mut lock = self.0.lock();
         let Some(mut callback) = lock.input_callback.take() else {
@@ -152,7 +167,7 @@ impl PlatformWindow for TestWindow {
     }
 
     fn appearance(&self) -> WindowAppearance {
-        WindowAppearance::Light
+        self.0.lock().appearance
     }
 
     fn display(&self) -> Option<std::rc::Rc<dyn crate::PlatformDisplay>> {
@@ -290,7 +305,9 @@ impl PlatformWindow for TestWindow {
         self.0.lock().hit_test_window_control_callback = Some(callback);
     }
 
-    fn on_appearance_changed(&self, _callback: Box<dyn FnMut()>) {}
+    fn on_appearance_changed(&self, callback: Box<dyn FnMut()>) {
+        self.0.lock().appearance_change_callback = Some(callback);
+    }
 
     fn draw(&self, scene: &Scene) {
         let scale_factor = self.scale_factor();
diff --git a/crates/gpui/src/window.rs b/crates/gpui/src/window.rs
index 048988a431..c2e1737641 100644
--- a/crates/gpui/src/window.rs
+++ b/crates/gpui/src/window.rs
@@ -1688,11 +1688,19 @@ impl Window {
             }
         }));
         platform_window.on_appearance_changed(Box::new({
-            let mut cx = cx.to_async();
+            let cx = cx.to_async();
+            let foreground_executor = cx.foreground_executor().clone();
             move || {
-                handle
-                    .update(&mut cx, |_, window, cx| window.appearance_changed(cx))
-                    .log_err();
+                let mut cx = cx.clone();
+                // Defer the update because changing the AppKit appearance may
+                // synchronously invoke this callback while App is already borrowed.
+                foreground_executor
+                    .spawn(async move {
+                        handle
+                            .update(&mut cx, |_, window, cx| window.appearance_changed(cx))
+                            .log_err();
+                    })
+                    .detach();
             }
         }));
         platform_window.on_button_layout_changed(Box::new({
@@ -6681,8 +6689,8 @@ mod tests {
 
     use crate::{
         AppContext as _, Bounds, Context, FocusHandle, InteractiveElement as _, IntoElement,
-        ParentElement, Pixels, Render, Styled, TestAppContext, Window, WindowOptions, canvas, div,
-        px, size,
+        ParentElement, Pixels, Render, Styled, TestAppContext, Window, WindowAppearance,
+        WindowOptions, canvas, div, px, size,
     };
 
     struct EmptyView;
@@ -6743,6 +6751,31 @@ mod tests {
             .unwrap();
     }
 
+    #[gpui::test]
+    fn test_appearance_change_runs_after_app_update(cx: &mut TestAppContext) {
+        let window = cx.add_window(|_, _| EmptyView);
+        let observed_appearance = Rc::new(Cell::new(None));
+        let _subscription = window
+            .update(cx, {
+                let observed_appearance = observed_appearance.clone();
+                move |_, window, _| {
+                    window.observe_window_appearance(move |window, _| {
+                        observed_appearance.set(Some(window.appearance()));
+                    })
+                }
+            })
+            .unwrap();
+        let test_window = cx.test_window(window.into());
+
+        cx.update(|_| {
+            test_window.simulate_appearance_change(WindowAppearance::Dark);
+            assert_eq!(observed_appearance.get(), None);
+        });
+        cx.run_until_parked();
+
+        assert_eq!(observed_appearance.get(), Some(WindowAppearance::Dark));
+    }
+
     struct RootView {
         explicit_size: bool,
         child_bounds: Rc<Cell<Bounds<Pixels>>>,
diff --git a/crates/gpui_macos/src/window.rs b/crates/gpui_macos/src/window.rs
index d094211516..cf9beb0228 100644
--- a/crates/gpui_macos/src/window.rs
+++ b/crates/gpui_macos/src/window.rs
@@ -2849,8 +2849,7 @@ extern "C" fn view_did_change_effective_appearance(this: &Object, _: Sel) {
         }
 
         // AppKit can relayout the standard traffic light buttons as part of
-        // applying a new appearance. Reapply GPUI's custom position after
-        // notifying appearance observers.
+        // applying a new appearance, so reapply GPUI's custom position.
         state.lock().move_traffic_light();
     }
 }