diff --git a/Riot/Assets/en.lproj/Vector.strings b/Riot/Assets/en.lproj/Vector.strings
index a168812bd4..e48b07dc33 100644
--- a/Riot/Assets/en.lproj/Vector.strings
+++ b/Riot/Assets/en.lproj/Vector.strings
@@ -767,6 +767,7 @@ Tap the + to start adding people.";
 "settings_ui_language" = "Language";
 "settings_ui_theme" = "Theme";
 "settings_ui_theme_auto" = "Auto";
+"settings_ui_theme_autoblack" = "Auto (Black)";
 "settings_ui_theme_light" = "Light";
 "settings_ui_theme_dark" = "Dark";
 "settings_ui_theme_black" = "Black";
diff --git a/Riot/Generated/Strings.swift b/Riot/Generated/Strings.swift
index 1ff68cf26f..d4d695ccf8 100644
--- a/Riot/Generated/Strings.swift
+++ b/Riot/Generated/Strings.swift
@@ -7795,6 +7795,10 @@ public class VectorL10n: NSObject {
   public static var settingsUiThemeAuto: String { 
     return VectorL10n.tr("Vector", "settings_ui_theme_auto") 
   }
+  /// Auto (Black)
+  public static var settingsUiThemeAutoBlack: String {
+    return VectorL10n.tr("Vector", "settings_ui_theme_autoblack")
+  }
   /// Black
   public static var settingsUiThemeBlack: String { 
     return VectorL10n.tr("Vector", "settings_ui_theme_black") 
diff --git a/Riot/Managers/Theme/ThemeService.m b/Riot/Managers/Theme/ThemeService.m
index 9d544ddce7..0602a2d2eb 100644
--- a/Riot/Managers/Theme/ThemeService.m
+++ b/Riot/Managers/Theme/ThemeService.m
@@ -74,6 +74,20 @@ - (void)setTheme:(id<Theme> _Nonnull)theme
         }
     }
 
+    if ([themeId isEqualToString:@"autoblack"])
+    {
+        if (@available(iOS 13, *))
+        {
+            // Translate "auto" into a theme with UITraitCollection
+            themeId = ([UITraitCollection currentTraitCollection].userInterfaceStyle == UIUserInterfaceStyleDark) ? @"black" : @"light";
+        }
+        else
+        {
+            // Translate "auto" into a theme
+            themeId = UIAccessibilityIsInvertColorsEnabled() ? @"black" : @"light";
+        }
+    }
+
     if ([themeId isEqualToString:@"dark"])
     {
         theme = [DarkTheme new];
diff --git a/Riot/Modules/Settings/SettingsViewController.m b/Riot/Modules/Settings/SettingsViewController.m
index 54bb95d34e..f5d0dfa55c 100644
--- a/Riot/Modules/Settings/SettingsViewController.m
+++ b/Riot/Modules/Settings/SettingsViewController.m
@@ -3887,7 +3887,7 @@ - (void)showThemePicker
 {
     __weak typeof(self) weakSelf = self;
 
-    __block UIAlertAction *autoAction, *lightAction, *darkAction, *blackAction;
+    __block UIAlertAction *autoAction, *autoBlackAction, *lightAction, *darkAction, *blackAction;
     NSString *themePickerMessage;
 
     void (^actionBlock)(UIAlertAction *action) = ^(UIAlertAction * action) {
@@ -3913,6 +3913,10 @@ - (void)showThemePicker
             {
                 newTheme = @"black";
             }
+            else if (action == autoBlackAction)
+            {
+                newTheme = @"autoblack";
+            }
 
             NSString *theme = RiotSettings.shared.userInterfaceTheme;
             if (newTheme && ![newTheme isEqualToString:theme])
@@ -3938,6 +3942,11 @@ - (void)showThemePicker
                                           style:UIAlertActionStyleDefault
                                         handler:actionBlock];
 
+    autoBlackAction = [UIAlertAction actionWithTitle:[VectorL10n settingsUiThemeAutoBlack]
+                                          style:UIAlertActionStyleDefault
+                                        handler:actionBlock];
+
+
     // Explain what is "auto"
     if (@available(iOS 13, *))
     {
@@ -3970,6 +3979,10 @@ - (void)showThemePicker
     {
         [themePicker addAction:autoAction];
     }
+    if (autoBlackAction)
+    {
+        [themePicker addAction:autoBlackAction];
+    }
     [themePicker addAction:lightAction];
     [themePicker addAction:darkAction];
     [themePicker addAction:blackAction];
diff --git a/changelog.d/5966.feature b/changelog.d/5966.feature
new file mode 100644
index 0000000000..72a75d5b3c
--- /dev/null
+++ b/changelog.d/5966.feature
@@ -0,0 +1 @@
+ThemeService: add a 'Auto (Black)' theme option (@tamcore)