diff --git a/src/changelog/unreleased.md b/src/changelog/unreleased.md
index 9f7b74bd05..6d4d3e6a5d 100644
--- a/src/changelog/unreleased.md
+++ b/src/changelog/unreleased.md
@@ -42,6 +42,7 @@ changelog entry.
 
 ### Added
 
+- Add `ActiveEventLoop::system_theme()`, returning the current system theme.
 - On Web, implement `Error` for `platform::web::CustomCursorError`.
 - On Android, add `{Active,}EventLoopExtAndroid::android_app()` to access the app used to create the loop.
 
@@ -50,3 +51,4 @@ changelog entry.
 - On MacOS, fix building with `feature = "rwh_04"`.
 - On Web, pen events are now routed through to `WindowEvent::Cursor*`.
 - On macOS, fix panic when releasing not available monitor.
+- On MacOS, return the system theme in `Window::theme()` if no theme override is set.
diff --git a/src/event_loop.rs b/src/event_loop.rs
index 99e72040f8..b5d5d26402 100644
--- a/src/event_loop.rs
+++ b/src/event_loop.rs
@@ -23,7 +23,7 @@ use crate::error::{EventLoopError, OsError};
 use crate::event::Event;
 use crate::monitor::MonitorHandle;
 use crate::platform_impl;
-use crate::window::{CustomCursor, CustomCursorSource, Window, WindowAttributes};
+use crate::window::{CustomCursor, CustomCursorSource, Theme, Window, WindowAttributes};
 
 /// Provides a way to retrieve events from the system and from the windows that were registered to
 /// the events loop.
@@ -437,6 +437,17 @@ impl ActiveEventLoop {
         self.p.listen_device_events(allowed);
     }
 
+    /// Returns the current system theme.
+    ///
+    /// Returns `None` if it cannot be determined on the current platform.
+    ///
+    /// ## Platform-specific
+    ///
+    /// - **iOS / Android / Wayland / x11 / Orbital:** Unsupported.
+    pub fn system_theme(&self) -> Option<Theme> {
+        self.p.system_theme()
+    }
+
     /// Sets the [`ControlFlow`].
     pub fn set_control_flow(&self, control_flow: ControlFlow) {
         self.p.set_control_flow(control_flow)
diff --git a/src/platform_impl/android/mod.rs b/src/platform_impl/android/mod.rs
index 9b12eaaa1d..950e310299 100644
--- a/src/platform_impl/android/mod.rs
+++ b/src/platform_impl/android/mod.rs
@@ -677,6 +677,11 @@ impl ActiveEventLoop {
         rwh_05::RawDisplayHandle::Android(rwh_05::AndroidDisplayHandle::empty())
     }
 
+    #[inline]
+    pub fn system_theme(&self) -> Option<Theme> {
+        None
+    }
+
     #[cfg(feature = "rwh_06")]
     #[inline]
     pub fn raw_display_handle_rwh_06(
diff --git a/src/platform_impl/ios/event_loop.rs b/src/platform_impl/ios/event_loop.rs
index ac485b9e8f..52d8062bea 100644
--- a/src/platform_impl/ios/event_loop.rs
+++ b/src/platform_impl/ios/event_loop.rs
@@ -22,8 +22,8 @@ use crate::event_loop::{
     ActiveEventLoop as RootActiveEventLoop, ControlFlow, DeviceEvents, EventLoopClosed,
 };
 use crate::platform::ios::Idiom;
-use crate::platform_impl::platform::app_state::{EventLoopHandler, HandlePendingUserEvents};
-use crate::window::{CustomCursor, CustomCursorSource};
+use crate::platform_impl::ios::app_state::{EventLoopHandler, HandlePendingUserEvents};
+use crate::window::{CustomCursor, CustomCursorSource, Theme};
 
 use super::app_delegate::AppDelegate;
 use super::app_state::AppState;
@@ -58,6 +58,11 @@ impl ActiveEventLoop {
         rwh_05::RawDisplayHandle::UiKit(rwh_05::UiKitDisplayHandle::empty())
     }
 
+    #[inline]
+    pub fn system_theme(&self) -> Option<Theme> {
+        None
+    }
+
     #[cfg(feature = "rwh_06")]
     #[inline]
     pub fn raw_display_handle_rwh_06(
diff --git a/src/platform_impl/linux/mod.rs b/src/platform_impl/linux/mod.rs
index 6cb99fee31..bee440189d 100644
--- a/src/platform_impl/linux/mod.rs
+++ b/src/platform_impl/linux/mod.rs
@@ -897,6 +897,11 @@ impl ActiveEventLoop {
         x11_or_wayland!(match self; Self(evlp) => evlp.raw_display_handle_rwh_05())
     }
 
+    #[inline]
+    pub fn system_theme(&self) -> Option<Theme> {
+        None
+    }
+
     #[cfg(feature = "rwh_06")]
     #[inline]
     pub fn raw_display_handle_rwh_06(
diff --git a/src/platform_impl/macos/event_loop.rs b/src/platform_impl/macos/event_loop.rs
index 1680953c34..9b7be282f6 100644
--- a/src/platform_impl/macos/event_loop.rs
+++ b/src/platform_impl/macos/event_loop.rs
@@ -16,7 +16,7 @@ use core_foundation::runloop::{
 };
 use objc2::rc::{autoreleasepool, Retained};
 use objc2::runtime::ProtocolObject;
-use objc2::{msg_send_id, ClassType};
+use objc2::{msg_send_id, sel, ClassType};
 use objc2_app_kit::{NSApplication, NSApplicationActivationPolicy, NSWindow};
 use objc2_foundation::{MainThreadMarker, NSObjectProtocol};
 
@@ -33,7 +33,7 @@ use crate::event_loop::{
 use crate::platform::macos::ActivationPolicy;
 use crate::platform::pump_events::PumpStatus;
 use crate::platform_impl::platform::cursor::CustomCursor;
-use crate::window::{CustomCursor as RootCustomCursor, CustomCursorSource};
+use crate::window::{CustomCursor as RootCustomCursor, CustomCursorSource, Theme};
 
 #[derive(Default)]
 pub struct PanicInfo {
@@ -106,6 +106,17 @@ impl ActiveEventLoop {
         rwh_05::RawDisplayHandle::AppKit(rwh_05::AppKitDisplayHandle::empty())
     }
 
+    #[inline]
+    pub fn system_theme(&self) -> Option<Theme> {
+        let app = NSApplication::sharedApplication(self.mtm);
+
+        if app.respondsToSelector(sel!(effectiveAppearance)) {
+            Some(super::window_delegate::appearance_to_theme(&app.effectiveAppearance()))
+        } else {
+            Some(Theme::Light)
+        }
+    }
+
     #[cfg(feature = "rwh_06")]
     #[inline]
     pub fn raw_display_handle_rwh_06(
diff --git a/src/platform_impl/macos/window_delegate.rs b/src/platform_impl/macos/window_delegate.rs
index a946dcf00f..2a7877b8bc 100644
--- a/src/platform_impl/macos/window_delegate.rs
+++ b/src/platform_impl/macos/window_delegate.rs
@@ -1645,14 +1645,18 @@ impl WindowDelegate {
     }
 
     pub fn theme(&self) -> Option<Theme> {
-        // Note: We could choose between returning the value of `effectiveAppearance` or
-        // `appearance`, depending on what the user is asking about:
-        // - "how should I render on this particular frame".
-        // - "what is the configuration for this window".
-        //
-        // We choose the latter for consistency with the `set_theme` call, though it might also be
-        // useful to expose the former.
-        Some(appearance_to_theme(unsafe { &*self.window().appearance()? }))
+        unsafe { self.window().appearance() }
+            .map(|appearance| appearance_to_theme(&appearance))
+            .or_else(|| {
+                let mtm = MainThreadMarker::from(self);
+                let app = NSApplication::sharedApplication(mtm);
+
+                if app.respondsToSelector(sel!(effectiveAppearance)) {
+                    Some(super::window_delegate::appearance_to_theme(&app.effectiveAppearance()))
+                } else {
+                    Some(Theme::Light)
+                }
+            })
     }
 
     pub fn set_theme(&self, theme: Option<Theme>) {
@@ -1835,7 +1839,7 @@ fn dark_appearance_name() -> &'static NSString {
     ns_string!("NSAppearanceNameDarkAqua")
 }
 
-fn appearance_to_theme(appearance: &NSAppearance) -> Theme {
+pub fn appearance_to_theme(appearance: &NSAppearance) -> Theme {
     let best_match = appearance.bestMatchFromAppearancesWithNames(&NSArray::from_id_slice(&[
         unsafe { NSAppearanceNameAqua.copy() },
         dark_appearance_name().copy(),
diff --git a/src/platform_impl/orbital/event_loop.rs b/src/platform_impl/orbital/event_loop.rs
index 59ba9e522d..91f76e7591 100644
--- a/src/platform_impl/orbital/event_loop.rs
+++ b/src/platform_impl/orbital/event_loop.rs
@@ -20,7 +20,7 @@ use crate::keyboard::{
     PhysicalKey,
 };
 use crate::window::{
-    CustomCursor as RootCustomCursor, CustomCursorSource, WindowId as RootWindowId,
+    CustomCursor as RootCustomCursor, CustomCursorSource, Theme, WindowId as RootWindowId,
 };
 
 use super::{
@@ -775,6 +775,11 @@ impl ActiveEventLoop {
         rwh_05::RawDisplayHandle::Orbital(rwh_05::OrbitalDisplayHandle::empty())
     }
 
+    #[inline]
+    pub fn system_theme(&self) -> Option<Theme> {
+        None
+    }
+
     #[cfg(feature = "rwh_06")]
     #[inline]
     pub fn raw_display_handle_rwh_06(
diff --git a/src/platform_impl/web/event_loop/window_target.rs b/src/platform_impl/web/event_loop/window_target.rs
index 05f87dcc35..d741f09872 100644
--- a/src/platform_impl/web/event_loop/window_target.rs
+++ b/src/platform_impl/web/event_loop/window_target.rs
@@ -614,6 +614,16 @@ impl ActiveEventLoop {
         self.runner.listen_device_events(allowed)
     }
 
+    pub fn system_theme(&self) -> Option<Theme> {
+        backend::is_dark_mode(self.runner.window()).map(|is_dark_mode| {
+            if is_dark_mode {
+                Theme::Dark
+            } else {
+                Theme::Light
+            }
+        })
+    }
+
     pub(crate) fn set_control_flow(&self, control_flow: ControlFlow) {
         self.runner.set_control_flow(control_flow)
     }
diff --git a/src/platform_impl/windows/dark_mode.rs b/src/platform_impl/windows/dark_mode.rs
index 4f910ad5c9..9d4bad9279 100644
--- a/src/platform_impl/windows/dark_mode.rs
+++ b/src/platform_impl/windows/dark_mode.rs
@@ -123,7 +123,7 @@ fn set_dark_mode_for_window(hwnd: HWND, is_dark_mode: bool) -> bool {
     }
 }
 
-fn should_use_dark_mode() -> bool {
+pub fn should_use_dark_mode() -> bool {
     should_apps_use_dark_mode() && !is_high_contrast()
 }
 
diff --git a/src/platform_impl/windows/event_loop.rs b/src/platform_impl/windows/event_loop.rs
index 35e3410d15..639a93865d 100644
--- a/src/platform_impl/windows/event_loop.rs
+++ b/src/platform_impl/windows/event_loop.rs
@@ -81,7 +81,7 @@ use crate::platform_impl::platform::{
     raw_input, util, wrap_device_id, Fullscreen, WindowId, DEVICE_ID,
 };
 use crate::window::{
-    CustomCursor as RootCustomCursor, CustomCursorSource, WindowId as RootWindowId,
+    CustomCursor as RootCustomCursor, CustomCursorSource, Theme, WindowId as RootWindowId,
 };
 use runner::{EventLoopRunner, EventLoopRunnerShared};
 
@@ -550,6 +550,10 @@ impl ActiveEventLoop {
         raw_input::register_all_mice_and_keyboards_for_raw_input(self.thread_msg_target, allowed);
     }
 
+    pub fn system_theme(&self) -> Option<Theme> {
+        Some(if super::dark_mode::should_use_dark_mode() { Theme::Dark } else { Theme::Light })
+    }
+
     pub(crate) fn set_control_flow(&self, control_flow: ControlFlow) {
         self.runner_shared.set_control_flow(control_flow)
     }
diff --git a/src/window.rs b/src/window.rs
index 31ef19a330..f19265e3a1 100644
--- a/src/window.rs
+++ b/src/window.rs
@@ -1371,14 +1371,14 @@ impl Window {
         self.window.maybe_queue_on_main(move |w| w.set_theme(theme))
     }
 
-    /// Returns the current window theme override.
+    /// Returns the current window theme.
     ///
-    /// Returns `None` if the current theme is set as the system default, or if it cannot be
-    /// determined on the current platform.
+    /// Returns `None` if it cannot be determined on the current platform.
     ///
     /// ## Platform-specific
     ///
-    /// - **iOS / Android / Wayland / x11 / Orbital:** Unsupported, returns `None`.
+    /// - **iOS / Android / x11 / Orbital:** Unsupported.
+    /// - **Wayland:** Only returns theme overrides.
     #[inline]
     pub fn theme(&self) -> Option<Theme> {
         let _span = tracing::debug_span!("winit::Window::theme",).entered();