diff --git a/src/ConfigMigrator.cs b/src/ConfigMigrator.cs
index 34908b6..e11cc08 100644
--- a/src/ConfigMigrator.cs
+++ b/src/ConfigMigrator.cs
@@ -24,6 +24,7 @@ public class OldAppConfigV4
         public string latitude { get; set; }
         public string longitude { get; set; }
         public bool darkMode { get; set; }
+        public bool autoDarkMode { get; set; }
         public bool hideTrayIcon { get; set; }
         public bool disableAutoUpdate { get; set; }
         public string lastUpdateCheck { get; set; }
@@ -146,6 +147,7 @@ private static void UpdateToVersion5(string jsonText)  // Added 2021-11-30
                 sunriseSunsetDuration = oldSettings.sunriseSunsetDuration,
                 activeThemes = new string[] { oldSettings.themeName },
                 darkMode = oldSettings.darkMode,
+                autoDarkMode = oldSettings.autoDarkMode,
                 enableShuffle = oldSettings.enableShuffle,
                 lastShuffleDate = oldSettings.lastShuffleDate != null ? SafeParse(
                     oldSettings.lastShuffleDate).ToString(CultureInfo.InvariantCulture) : null,
diff --git a/src/JsonConfig.cs b/src/JsonConfig.cs
index f34aa6d..c9a1140 100644
--- a/src/JsonConfig.cs
+++ b/src/JsonConfig.cs
@@ -31,6 +31,7 @@ public class AppConfig : INotifyPropertyChanged
         // Theme settings
         public string[] activeThemes { get; set; }
         public bool darkMode { get; set; }
+        public bool autoDarkMode { get; set; }
         public bool changeLockScreen { get; set; }
         public bool enableShuffle { get; set; }
         public string lastShuffleDate { get; set; }
diff --git a/src/MainMenu.cs b/src/MainMenu.cs
index 0821d80..76fcc46 100644
--- a/src/MainMenu.cs
+++ b/src/MainMenu.cs
@@ -14,6 +14,7 @@ class MainMenu
         private static readonly Func<string, string> _ = Localization.GetTranslation;
         public static ToolStripMenuItem themeItem;
         public static ToolStripMenuItem darkModeItem;
+        public static ToolStripMenuItem autoDarkMode;
         public static ToolStripMenuItem startOnBootItem;
         public static ToolStripMenuItem enableScriptsItem;
         public static ToolStripMenuItem shuffleItem;
@@ -51,6 +52,8 @@ private static List<ToolStripItem> GetMenuItems()
             items.AddRange(LockScreenChanger.GetMenuItems());
             darkModeItem = new ToolStripMenuItem(_("Enable &Night Mode"), null, OnDarkModeClick);
             darkModeItem.Checked = JsonConfig.settings.darkMode;
+            autoDarkMode = new ToolStripMenuItem(_("Enable Auto Dark Mode"), null, OnAutoDarkModeClick);
+            autoDarkMode.Checked = JsonConfig.settings.autoDarkMode;
             startOnBootItem = new ToolStripMenuItem(_("Start on &Boot"), null, OnStartOnBootClick);
 
             ToolStripMenuItem optionsItem = new ToolStripMenuItem(_("More &Options"));
@@ -59,6 +62,7 @@ private static List<ToolStripItem> GetMenuItems()
             items.AddRange(new List<ToolStripItem>()
             {
                 darkModeItem,
+                autoDarkMode,
                 startOnBootItem,
                 optionsItem,
                 new ToolStripSeparator(),
@@ -121,6 +125,11 @@ private static void OnDarkModeClick(object sender, EventArgs e)
             AppContext.wpEngine.ToggleDarkMode();
         }
 
+        private static void OnAutoDarkModeClick(object sender, EventArgs e)
+        {
+            AppContext.wpEngine.ToggleAutoDarkMode();
+        }
+
         private static void OnStartOnBootClick(object sender, EventArgs e)
         {
             UwpDesktop.GetHelper().ToggleStartOnBoot();
diff --git a/src/WallpaperEngine.cs b/src/WallpaperEngine.cs
index 6c41c37..6801167 100644
--- a/src/WallpaperEngine.cs
+++ b/src/WallpaperEngine.cs
@@ -32,7 +32,7 @@ class WallpaperEngine
         private System.Timers.Timer backgroundTimer = new System.Timers.Timer();
         private System.Timers.Timer schedulerTimer = new System.Timers.Timer();
         private const long timerError = (long)(TimeSpan.TicksPerMillisecond * 15.6);
-
+        
         public WallpaperEngine()
         {
             fullScreenChecker = new FullScreenApi(this);
@@ -91,6 +91,11 @@ public void RunScheduler(bool forceImageUpdate = false)
                 if (displayEvents[i].currentTheme != null)
                 {
                     SetWallpaper(displayEvents[i]);
+                    
+                    if (JsonConfig.settings.autoDarkMode)
+                    {
+                        SwitchTheme(data);
+                    }
 
                     if (displayEvents[i].nextUpdateTime.Ticks < nextDisplayUpdateTicks)
                     {
@@ -141,6 +146,13 @@ public void ToggleDarkMode()
             RunScheduler();
         }
 
+        public void ToggleAutoDarkMode()
+        {
+            bool isEnabled = JsonConfig.settings.autoDarkMode ^ true;
+            JsonConfig.settings.autoDarkMode = isEnabled;
+            MainMenu.autoDarkMode.Checked = isEnabled;
+        }
+
         private bool UpdateDisplayList()
         {
             if (JsonConfig.settings.activeThemes == null || JsonConfig.settings.activeThemes[0] != null)
@@ -185,6 +197,22 @@ private void SetWallpaper(DisplayEvent e)
             e.lastImagePath = imagePath;
         }
 
+        public void SwitchTheme(SolarData data)
+        {
+            RegistryKey key = Registry.CurrentUser.OpenSubKey(@"Software\Microsoft\Windows\CurrentVersion\Themes\Personalize", true);
+
+            if (DateTime.Now.TimeOfDay >= data.sunsetTime.TimeOfDay)
+            {
+                key.SetValue("AppsUseLightTheme", 0, RegistryValueKind.DWord);
+                key.SetValue("SystemUsesLightTheme", 0, RegistryValueKind.DWord);
+            }
+            else if (DateTime.Now.TimeOfDay >= data.sunriseTime.TimeOfDay)
+            {
+                key.SetValue("AppsUseLightTheme", 1, RegistryValueKind.DWord);
+                key.SetValue("SystemUsesLightTheme", 1, RegistryValueKind.DWord);
+            }
+        }
+
         private void StartTimer(DateTime futureTime)
         {
             long intervalTicks = futureTime.Ticks - DateTime.Now.Ticks;