diff --git a/init.el b/init.el
index 2fc2119..7444b95 100644
--- a/init.el
+++ b/init.el
@@ -131,6 +131,14 @@
   (setq ef-themes-to-toggle '(ef-day ef-night))
   (mapc #'disable-theme custom-enabled-themes)
   (load-theme 'ef-night :no-confirm)
+  (when (eq window-system 'ns)
+    (defun dl/themes-toggle-with-system (appearance)
+      "Load dark or light theme depending on system appearance on macOS."
+      (mapc #'disable-theme custom-enabled-themes)
+      (pcase appearance
+	('light (load-theme 'ef-day :no-confirm))
+	('dark (load-theme 'ef-night :no-confirm))))
+    (add-hook 'ns-system-appearance-change-functions #'dl/themes-toggle-with-system))
   :bind ("<f12>" . ef-themes-toggle))
 
 (use-package diminish