diff --git a/apps/reader/locales/de-DE.ts b/apps/reader/locales/de-DE.ts
new file mode 100644
index 00000000..94dbd703
--- /dev/null
+++ b/apps/reader/locales/de-DE.ts
@@ -0,0 +1,77 @@
+export default {
+  'home.title': 'Startseite',
+  'home.share': 'Teilen',
+  'home.download': 'Herunterladen',
+  'home.download_sample_book': 'Beispielbuch herunterladen',
+  'home.select': 'Auswählen',
+  'home.cancel': 'Abbrechen',
+  'home.select_all': 'Alle auswählen',
+  'home.deselect_all': 'Alle abwählen',
+  'home.export': 'Exportieren',
+  'home.import': 'Importieren',
+  'home.upload': 'Hochladen',
+  'home.delete': 'Löschen',
+
+  'toc.title': 'Inhaltsverzeichnis',
+  'toc.library': 'Bibliothek',
+
+  'search.title': 'Suchen',
+  'search.files.result': '{n} Ergebnisse in {m} Abschnitten',
+
+  'annotation.title': 'Anmerkung',
+  'annotation.definitions': 'Definitionen',
+  'annotation.annotations': 'Anmerkungen',
+  'annotation.copy_as_markdown': 'Als Markdown kopieren',
+
+  'image.title': 'Bild',
+
+  'timeline.title': 'Zeitleiste',
+
+  'typography.title': 'Typografie',
+  'typography.scope.book': 'Buch',
+  'typography.scope.global': 'Global',
+  'typography.page_view': 'Seitenansicht',
+  'typography.page_view.single_page': 'Einzelseite',
+  'typography.page_view.double_page': 'Doppelseite',
+  'typography.font_family': 'Schriftart',
+  'typography.font_size': 'Schriftgröße',
+  'typography.font_weight': 'Schriftstärke',
+  'typography.line_height': 'Zeilenhöhe',
+  'typography.zoom': 'Zoom',
+
+  'theme.title': 'Design',
+  'theme.source_color': 'Quellfarbe',
+  'theme.background_color': 'Hintergrundfarbe',
+
+  'settings.title': 'Einstellungen',
+  'settings.language': 'Sprache',
+  'settings.color_scheme': 'Farbschema',
+  'settings.color_scheme.system': 'System',
+  'settings.color_scheme.light': 'Hell',
+  'settings.color_scheme.dark': 'Dunkel',
+  'settings.synchronization.title': 'Synchronisation',
+  'settings.synchronization.authorize': 'Autorisieren',
+  'settings.synchronization.unauthorize': 'Deautorisieren',
+  'settings.cache': 'Cache',
+  'settings.cache.clear': 'Leeren',
+  'settings.text_selection_menu': 'Textauswahlmenü',
+  'settings.text_selection_menu.enable': 'Aktivieren',
+
+  'menu.copy': 'Kopieren',
+  'menu.search_in_book': 'Im Buch suchen',
+  'menu.annotate': 'Kommentieren',
+  'menu.define': 'Definieren',
+  'menu.undefine': 'Definition entfernen',
+  'menu.create': 'Erstellen',
+  'menu.delete': 'Löschen',
+  'menu.update': 'Aktualisieren',
+
+  'action.expand_all': 'Alle erweitern',
+  'action.collapse_all': 'Alle einklappen',
+  'action.close': 'Schließen',
+  'action.clear': 'Leeren',
+  'action.step_down': 'Schritt zurück',
+  'action.step_up': 'Schritt vor',
+
+  untitled: 'Ohne Titel',
+} as const
diff --git a/apps/reader/locales/index.ts b/apps/reader/locales/index.ts
index 205e4ad1..9bb27c88 100644
--- a/apps/reader/locales/index.ts
+++ b/apps/reader/locales/index.ts
@@ -1,10 +1,20 @@
 import en_US from '../locales/en-US'
 import ja_JP from '../locales/ja-JP'
 import zh_CN from '../locales/zh-CN'
+import de_DE from '../locales/de-DE'
+
+// Locale display names
+export const localeNames: Record<string, string> = {
+  'en-US': 'English',
+  'zh-CN': '简体中文',
+  'ja-JP': '日本語',
+  'de-DE': 'Deutsch',
+}
 
 // eslint-disable-next-line import/no-anonymous-default-export
 export default {
   'en-US': en_US,
   'zh-CN': zh_CN,
   'ja-JP': ja_JP,
+  'de-DE': de_DE,
 } as const
diff --git a/apps/reader/next.config.js b/apps/reader/next.config.js
index 18ebde29..b69bf4b0 100644
--- a/apps/reader/next.config.js
+++ b/apps/reader/next.config.js
@@ -40,7 +40,7 @@ const config = {
     return config
   },
   i18n: {
-    locales: ['en-US', 'zh-CN', 'ja-JP'],
+    locales: ['en-US', 'zh-CN', 'ja-JP', 'de-DE'],
     defaultLocale: 'en-US',
   },
   ...(IS_DOCKER && {
diff --git a/apps/reader/src/components/pages/settings.tsx b/apps/reader/src/components/pages/settings.tsx
index ae9227d0..ea6d2428 100644
--- a/apps/reader/src/components/pages/settings.tsx
+++ b/apps/reader/src/components/pages/settings.tsx
@@ -9,6 +9,7 @@ import {
   useForceRender,
   useTranslation,
 } from '@flow/reader/hooks'
+import { localeNames } from '@flow/reader/locales'
 import { useSettings } from '@flow/reader/state'
 import { dbx, mapToToken, OAUTH_SUCCESS_MESSAGE } from '@flow/reader/sync'
 
@@ -18,7 +19,7 @@ import { Page } from '../Page'
 
 export const Settings: React.FC = () => {
   const { scheme, setScheme } = useColorScheme()
-  const { asPath, push, locale } = useRouter()
+  const { asPath, push, locale, locales } = useRouter()
   const [settings, setSettings] = useSettings()
   const t = useTranslation('settings')
 
@@ -32,9 +33,11 @@ export const Settings: React.FC = () => {
               push(asPath, undefined, { locale: e.target.value })
             }}
           >
-            <option value="en-US">English</option>
-            <option value="zh-CN">简体中文</option>
-            <option value="ja-JP">日本語</option>
+            {locales?.map((loc) => (
+              <option key={loc} value={loc}>
+                {localeNames[loc] || loc}
+              </option>
+            ))}
           </Select>
         </Item>
         <Item title={t('color_scheme')}>