diff --git a/app/src/main/java/org/shadowice/flocke/andotp/Activities/MainActivity.java b/app/src/main/java/org/shadowice/flocke/andotp/Activities/MainActivity.java
index 8c391422..5c89ab99 100644
--- a/app/src/main/java/org/shadowice/flocke/andotp/Activities/MainActivity.java
+++ b/app/src/main/java/org/shadowice/flocke/andotp/Activities/MainActivity.java
@@ -387,7 +387,8 @@ public class MainActivity extends BaseActivity
                 key.equals(getString(R.string.settings_key_enable_screenshot)) ||
                 key.equals(getString(R.string.settings_key_tag_functionality)) ||
                 key.equals(getString(R.string.settings_key_label_highlight_token)) ||
-                key.equals(getString(R.string.settings_key_card_layout))) {
+                key.equals(getString(R.string.settings_key_card_layout)) ||
+                key.equals(getString(R.string.settings_key_theme_mode))) {
             recreate();
         }
     }
diff --git a/app/src/main/java/org/shadowice/flocke/andotp/Activities/SettingsActivity.java b/app/src/main/java/org/shadowice/flocke/andotp/Activities/SettingsActivity.java
index b2fd7f18..c015d7da 100644
--- a/app/src/main/java/org/shadowice/flocke/andotp/Activities/SettingsActivity.java
+++ b/app/src/main/java/org/shadowice/flocke/andotp/Activities/SettingsActivity.java
@@ -27,6 +27,7 @@ import android.app.AlertDialog;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.SharedPreferences;
+import android.os.Build;
 import android.os.Bundle;
 import android.preference.CheckBoxPreference;
 import android.preference.EditTextPreference;
@@ -123,7 +124,8 @@ public class SettingsActivity extends BaseActivity
 
         if (key.equals(getString(R.string.settings_key_theme)) ||
                 key.equals(getString(R.string.settings_key_locale)) ||
-                key.equals(getString(R.string.settings_key_special_features))) {
+                key.equals(getString(R.string.settings_key_special_features)) ||
+                key.equals(getString(R.string.settings_key_theme_mode))) {
             recreate();
         } else if(key.equals(getString(R.string.settings_key_encryption))) {
             if (settings.getEncryption() != EncryptionType.PASSWORD) {
@@ -240,6 +242,7 @@ public class SettingsActivity extends BaseActivity
 
     public static class SettingsFragment extends PreferenceFragment {
         PreferenceCategory catSecurity;
+        PreferenceCategory catUI;
 
         Settings settings;
         ListPreference encryption;
@@ -249,6 +252,8 @@ public class SettingsActivity extends BaseActivity
         OpenPgpAppPreference pgpProvider;
         EditTextPreference pgpEncryptionKey;
         OpenPgpKeyPreference pgpSigningKey;
+        ListPreference themeMode;
+        ListPreference theme;
 
         public void encryptionChangeWithDialog(final EncryptionType encryptionType) {
             AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
@@ -292,7 +297,10 @@ public class SettingsActivity extends BaseActivity
 
             // Authentication
             catSecurity = (PreferenceCategory) findPreference(getString(R.string.settings_key_cat_security));
+            catUI = (PreferenceCategory) findPreference(getString(R.string.settings_key_cat_ui));
             encryption = (ListPreference) findPreference(getString(R.string.settings_key_encryption));
+            themeMode = (ListPreference) findPreference(getString(R.string.settings_key_theme_mode));
+            theme = (ListPreference) findPreference(getString(R.string.settings_key_theme));
 
             encryption.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
                 @Override
@@ -395,11 +403,21 @@ public class SettingsActivity extends BaseActivity
                         });
 
                         builder.create().show();
-
                         return false;
                     }
                 });
             }
+            //Remove Theme Mode selection option for devices below Android 10. Disable theme selection if Theme Mode is set auto
+            //TODO: 29 needs to be replaced with VERSION_CODE.Q when compileSdk and targetSdk is updated to 29
+            if(Build.VERSION.SDK_INT < 29) {
+                catUI.removePreference(themeMode);
+            } else {
+                if(sharedPref.getString(getString(R.string.settings_key_theme_mode),getString(R.string.settings_default_theme_mode)).equals("auto")) {
+                    theme.setEnabled(false);
+                } else {
+                    theme.setEnabled(true);
+                }
+            }
         }
     }
 }
diff --git a/app/src/main/java/org/shadowice/flocke/andotp/Utilities/Settings.java b/app/src/main/java/org/shadowice/flocke/andotp/Utilities/Settings.java
index 909b4470..a6517bc2 100644
--- a/app/src/main/java/org/shadowice/flocke/andotp/Utilities/Settings.java
+++ b/app/src/main/java/org/shadowice/flocke/andotp/Utilities/Settings.java
@@ -24,6 +24,8 @@ package org.shadowice.flocke.andotp.Utilities;
 
 import android.content.Context;
 import android.content.SharedPreferences;
+import android.content.res.Configuration;
+import android.os.Build;
 import android.preference.PreferenceManager;
 import android.util.Base64;
 
@@ -332,16 +334,34 @@ public class Settings {
     }
 
     public int getTheme() {
-        String themeName = getString(R.string.settings_key_theme, R.string.settings_default_theme);
-
         int theme = R.style.AppTheme_NoActionBar;
+        String themeMode = getString(R.string.settings_key_theme_mode, R.string.settings_default_theme_mode);
 
-        if (themeName.equals("light")) {
-            theme = R.style.AppTheme_NoActionBar;
-        } else if (themeName.equals("dark")) {
-            theme = R.style.AppTheme_Dark_NoActionBar;
-        } else if (themeName.equals("black")) {
-            theme = R.style.AppTheme_Black_NoActionBar;
+        //TODO: 29 needs to be replaced with VERSION_CODE.Q when compileSdk and targetSdk is updated to 29
+        if(Build.VERSION.SDK_INT >= 29 && themeMode.equals("auto")){
+            switch (context.getResources().getConfiguration().uiMode & Configuration.UI_MODE_NIGHT_MASK) {
+                //Dark Mode
+                case Configuration.UI_MODE_NIGHT_YES:
+                    theme = R.style.AppTheme_Dark_NoActionBar;
+                    break;
+                //Light Mode / Undefined mode / Default mode
+                case Configuration.UI_MODE_NIGHT_NO:
+                case Configuration.UI_MODE_NIGHT_UNDEFINED:
+                default:
+                    theme = R.style.AppTheme_NoActionBar;
+                    break;
+            }
+        } else {
+
+            String themeName = getString(R.string.settings_key_theme, R.string.settings_default_theme);
+
+            if (themeName.equals("light")) {
+                theme = R.style.AppTheme_NoActionBar;
+            } else if (themeName.equals("dark")) {
+                theme = R.style.AppTheme_Dark_NoActionBar;
+            } else if (themeName.equals("black")) {
+                theme = R.style.AppTheme_Black_NoActionBar;
+            }
         }
 
         return theme;
diff --git a/app/src/main/res/values/settings.xml b/app/src/main/res/values/settings.xml
index a8f6f6ca..345c96d2 100644
--- a/app/src/main/res/values/settings.xml
+++ b/app/src/main/res/values/settings.xml
@@ -17,8 +17,10 @@
     <string name="settings_key_panic" translatable="false">pref_panic</string>
     <string name="settings_key_relock_screen_off" translatable="false">pref_relock_screen_off</string>
 
+    <string name="settings_key_cat_ui" translatable="false">perf_cat_ui</string>
     <string name="settings_key_lang" translatable="false">pref_lang</string>                                <!-- Deprecated -->
     <string name="settings_key_locale" translatable="false">pref_locale</string>
+    <string name="settings_key_theme_mode" translatable="false">perf_theme_mode</string>
     <string name="settings_key_theme" translatable="false">pref_theme</string>
     <string name="settings_key_label_size" translatable="false">pref_label_size_sp</string>
     <string name="settings_key_card_layout" translatable="false">pref_card_layout</string>
@@ -59,6 +61,7 @@
     <integer name="settings_default_tap_to_reveal_timeout">30</integer>
     <string name="settings_default_encryption" translatable="false">keystore</string>
     <string name="settings_default_locale" translatable="false">system</string>
+    <string name="settings_default_theme_mode" translatable="false">auto</string>
     <string name="settings_default_theme" translatable="false">light</string>
     <integer name="settings_default_label_size">18</integer>
     <string name="settings_default_card_layout" translatable="false">default</string>
@@ -131,6 +134,11 @@
         <item>zh_TW</item>
     </string-array>
 
+    <string-array name="settings_values_theme_mode" translatable="false">
+        <item>auto</item>
+        <item>manual</item>
+    </string-array>
+
     <string-array name="settings_values_theme" translatable="false">
         <item>light</item>
         <item>dark</item>
diff --git a/app/src/main/res/values/strings_settings.xml b/app/src/main/res/values/strings_settings.xml
index 05396839..8eef0b71 100644
--- a/app/src/main/res/values/strings_settings.xml
+++ b/app/src/main/res/values/strings_settings.xml
@@ -18,6 +18,7 @@
     <string name="settings_title_relock_screen_off">Re-lock on screen off</string>
 
     <string name="settings_title_lang">Language</string>
+    <string name="settings_title_theme_mode">Theme Mode</string>
     <string name="settings_title_theme">Theme</string>
     <string name="settings_title_card_layout">Card layout</string>
     <string name="settings_title_label_size">Label font size</string>
@@ -167,6 +168,11 @@
         <item>Tags</item>
     </string-array>
 
+    <string-array name="settings_entries_theme_mode">
+        <item>Auto</item>
+        <item>Manual</item>
+    </string-array>
+
     <string-array name="settings_entries_theme">
         <item>Light theme</item>
         <item>Dark theme</item>
diff --git a/app/src/main/res/xml/preferences.xml b/app/src/main/res/xml/preferences.xml
index 857415cf..cf076d48 100644
--- a/app/src/main/res/xml/preferences.xml
+++ b/app/src/main/res/xml/preferences.xml
@@ -51,7 +51,8 @@
     </PreferenceCategory>
 
     <PreferenceCategory
-        android:title="@string/settings_category_title_ui">
+        android:title="@string/settings_category_title_ui"
+        android:key="@string/settings_key_cat_ui">
 
         <ListPreference
             android:key="@string/settings_key_locale"
@@ -61,6 +62,14 @@
             android:entryValues="@array/settings_values_locale"
             android:defaultValue="@string/settings_default_locale" />
 
+        <ListPreference
+            android:key="@string/settings_key_theme_mode"
+            android:title="@string/settings_title_theme_mode"
+            android:summary="%s"
+            android:entries="@array/settings_entries_theme_mode"
+            android:entryValues="@array/settings_values_theme_mode"
+            android:defaultValue="@string/settings_default_theme_mode" />
+
         <ListPreference
             android:key="@string/settings_key_theme"
             android:title="@string/settings_title_theme"