diff --git a/app/src/main/java/eu/faircode/email/ActivityBase.java b/app/src/main/java/eu/faircode/email/ActivityBase.java
index 49a61359a5..4f984abae3 100644
--- a/app/src/main/java/eu/faircode/email/ActivityBase.java
+++ b/app/src/main/java/eu/faircode/email/ActivityBase.java
@@ -51,6 +51,12 @@ abstract class ActivityBase extends AppCompatActivity implements SharedPreferenc
 
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
         String theme = prefs.getString("theme", null);
+        if ("system".equals(theme)) {
+            int uiMode = getResources().getConfiguration().uiMode;
+            Log.i("UI mode=" + uiMode);
+            if ((uiMode & Configuration.UI_MODE_NIGHT_YES) != 0)
+                setTheme(R.style.AppThemeDark);
+        }
         if ("dark".equals(theme))
             setTheme(R.style.AppThemeDark);
         else if ("black".equals(theme))
diff --git a/app/src/main/java/eu/faircode/email/ActivitySetup.java b/app/src/main/java/eu/faircode/email/ActivitySetup.java
index 4a70411de9..81034bf6fe 100644
--- a/app/src/main/java/eu/faircode/email/ActivitySetup.java
+++ b/app/src/main/java/eu/faircode/email/ActivitySetup.java
@@ -143,6 +143,7 @@ public class ActivitySetup extends ActivityBilling implements FragmentManager.On
                     case R.string.title_setup_light_theme:
                     case R.string.title_setup_dark_theme:
                     case R.string.title_setup_black_theme:
+                    case R.string.title_setup_system_theme:
                         onMenuTheme(item.getId());
                         break;
                     case R.string.title_setup_notifications:
@@ -178,13 +179,15 @@ public class ActivitySetup extends ActivityBilling implements FragmentManager.On
             drawerArray.add(new DrawerItem(this, R.layout.item_drawer, R.drawable.baseline_unarchive_24, R.string.title_setup_import));
 
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
-        String theme = prefs.getString("theme", "light");
-        if ("dark".equals(theme))
+        String theme = prefs.getString("theme", "system");
+        if ("light".equals(theme))
+            drawerArray.add(new DrawerItem(this, R.layout.item_drawer, R.drawable.baseline_palette_24, R.string.title_setup_dark_theme));
+        else if ("dark".equals(theme))
             drawerArray.add(new DrawerItem(this, R.layout.item_drawer, R.drawable.baseline_palette_24, R.string.title_setup_black_theme));
         else if ("black".equals(theme))
-            drawerArray.add(new DrawerItem(this, R.layout.item_drawer, R.drawable.baseline_palette_24, R.string.title_setup_light_theme));
+            drawerArray.add(new DrawerItem(this, R.layout.item_drawer, R.drawable.baseline_palette_24, R.string.title_setup_system_theme));
         else
-            drawerArray.add(new DrawerItem(this, R.layout.item_drawer, R.drawable.baseline_palette_24, R.string.title_setup_dark_theme));
+            drawerArray.add(new DrawerItem(this, R.layout.item_drawer, R.drawable.baseline_palette_24, R.string.title_setup_light_theme));
 
         if (getIntentNotifications(this).resolveActivity(pm) != null)
             drawerArray.add(new DrawerItem(this, R.layout.item_drawer, R.drawable.baseline_notifications_24, R.string.title_setup_notifications));
@@ -375,6 +378,9 @@ public class ActivitySetup extends ActivityBilling implements FragmentManager.On
             case R.string.title_setup_black_theme:
                 prefs.edit().putString("theme", "black").apply();
                 break;
+            case R.string.title_setup_system_theme:
+                prefs.edit().putString("theme", "system").apply();
+                break;
         }
     }
 
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 499a012a33..b5ff1c7bc4 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -128,6 +128,7 @@
     <string name="title_setup_light_theme">Light theme</string>
     <string name="title_setup_dark_theme">Dark theme</string>
     <string name="title_setup_black_theme">Black theme</string>
+    <string name="title_setup_system_theme">System theme</string>
     <string name="title_setup_defaults">Restore defaults</string>
 
     <string name="title_advanced">Advanced options</string>