diff --git a/package-lock.json b/package-lock.json
index 0261c3a..da2eedf 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -11074,7 +11074,7 @@
         },
         "packages/extension": {
             "name": "@page-agent/ext",
-            "version": "0.1.6",
+            "version": "0.1.7",
             "hasInstallScript": true,
             "dependencies": {
                 "@page-agent/core": "1.3.0",
diff --git a/packages/core/src/PageAgentCore.ts b/packages/core/src/PageAgentCore.ts
index 69d66eb..0a9c63c 100644
--- a/packages/core/src/PageAgentCore.ts
+++ b/packages/core/src/PageAgentCore.ts
@@ -7,7 +7,7 @@ import type { BrowserState, PageController } from '@page-agent/page-controller'
 import chalk from 'chalk'
 import * as zod from 'zod'
 
-import { type PageAgentConfig } from './config'
+import { type PageAgentConfig, type SupportedLanguage } from './config'
 import { DEFAULT_MAX_STEPS } from './config/constants'
 import SYSTEM_PROMPT from './prompts/system_prompt.md?raw'
 import { tools } from './tools'
@@ -24,6 +24,7 @@ import type {
 import { assert, normalizeResponse, uid, waitFor } from './utils'
 
 export { type PageAgentConfig }
+export type { SupportedLanguage }
 export { tool, type PageAgentTool } from './tools'
 export type * from './types'
 
diff --git a/packages/extension/package.json b/packages/extension/package.json
index 88213ae..4f5e8da 100644
--- a/packages/extension/package.json
+++ b/packages/extension/package.json
@@ -1,7 +1,7 @@
 {
     "name": "@page-agent/ext",
     "private": true,
-    "version": "0.1.6",
+    "version": "0.1.7",
     "type": "module",
     "scripts": {
         "dev": "wxt",
diff --git a/packages/extension/src/agent/useAgent.ts b/packages/extension/src/agent/useAgent.ts
index c734110..6b28c49 100644
--- a/packages/extension/src/agent/useAgent.ts
+++ b/packages/extension/src/agent/useAgent.ts
@@ -1,22 +1,34 @@
 /**
  * React hook for using AgentController
  */
-import type { AgentActivity, AgentStatus, HistoricalEvent } from '@page-agent/core'
+import type {
+	AgentActivity,
+	AgentStatus,
+	HistoricalEvent,
+	SupportedLanguage,
+} from '@page-agent/core'
 import type { LLMConfig } from '@page-agent/llms'
 import { useCallback, useEffect, useRef, useState } from 'react'
 
 import { MultiPageAgent } from './MultiPageAgent'
 import { DEMO_CONFIG } from './constants'
 
+/** Language preference: undefined means follow system */
+export type LanguagePreference = SupportedLanguage | undefined
+
+export interface ExtConfig extends LLMConfig {
+	language?: LanguagePreference
+}
+
 export interface UseAgentResult {
 	status: AgentStatus
 	history: HistoricalEvent[]
 	activity: AgentActivity | null
 	currentTask: string
-	config: LLMConfig | null
+	config: ExtConfig | null
 	execute: (task: string) => Promise<void>
 	stop: () => void
-	configure: (config: LLMConfig) => Promise<void>
+	configure: (config: ExtConfig) => Promise<void>
 }
 
 export function useAgent(): UseAgentResult {
@@ -25,16 +37,17 @@ export function useAgent(): UseAgentResult {
 	const [history, setHistory] = useState<HistoricalEvent[]>([])
 	const [activity, setActivity] = useState<AgentActivity | null>(null)
 	const [currentTask, setCurrentTask] = useState('')
-	const [config, setConfig] = useState<LLMConfig | null>(null)
+	const [config, setConfig] = useState<ExtConfig | null>(null)
 
 	useEffect(() => {
-		chrome.storage.local.get('llmConfig').then((result) => {
-			if (result.llmConfig) {
-				setConfig(result.llmConfig as LLMConfig)
-			} else {
+		chrome.storage.local.get(['llmConfig', 'language']).then((result) => {
+			const llmConfig = (result.llmConfig as LLMConfig) ?? DEMO_CONFIG
+			const language = (result.language as SupportedLanguage) || undefined
+			const full = { ...llmConfig, language }
+			if (!result.llmConfig) {
 				chrome.storage.local.set({ llmConfig: DEMO_CONFIG })
-				setConfig(DEMO_CONFIG)
 			}
+			setConfig(full)
 		})
 	}, [])
 
@@ -87,9 +100,14 @@ export function useAgent(): UseAgentResult {
 		agentRef.current?.stop()
 	}, [])
 
-	const configure = useCallback(async (newConfig: LLMConfig) => {
-		await chrome.storage.local.set({ llmConfig: newConfig })
-		setConfig(newConfig)
+	const configure = useCallback(async ({ language, ...llmConfig }: ExtConfig) => {
+		await chrome.storage.local.set({ llmConfig })
+		if (language) {
+			await chrome.storage.local.set({ language })
+		} else {
+			await chrome.storage.local.remove('language')
+		}
+		setConfig({ ...llmConfig, language })
 	}, [])
 
 	return {
diff --git a/packages/extension/src/entrypoints/sidepanel/components/ConfigPanel.tsx b/packages/extension/src/entrypoints/sidepanel/components/ConfigPanel.tsx
index 20bed01..968d833 100644
--- a/packages/extension/src/entrypoints/sidepanel/components/ConfigPanel.tsx
+++ b/packages/extension/src/entrypoints/sidepanel/components/ConfigPanel.tsx
@@ -1,15 +1,15 @@
-import type { LLMConfig } from '@page-agent/llms'
 import { Copy, CornerUpLeft, Eye, EyeOff, HatGlasses, Home, Loader2, Scale } from 'lucide-react'
 import { useEffect, useState } from 'react'
 import { siGithub } from 'simple-icons'
 
 import { DEMO_API_KEY, DEMO_BASE_URL, DEMO_MODEL } from '@/agent/constants'
+import type { ExtConfig, LanguagePreference } from '@/agent/useAgent'
 import { Button } from '@/components/ui/button'
 import { Input } from '@/components/ui/input'
 
 interface ConfigPanelProps {
-	config: LLMConfig | null
-	onSave: (config: LLMConfig) => Promise<void>
+	config: ExtConfig | null
+	onSave: (config: ExtConfig) => Promise<void>
 	onClose: () => void
 }
 
@@ -17,6 +17,7 @@ export function ConfigPanel({ config, onSave, onClose }: ConfigPanelProps) {
 	const [apiKey, setApiKey] = useState(config?.apiKey || DEMO_API_KEY)
 	const [baseURL, setBaseURL] = useState(config?.baseURL || DEMO_BASE_URL)
 	const [model, setModel] = useState(config?.model || DEMO_MODEL)
+	const [language, setLanguage] = useState<LanguagePreference>(config?.language)
 	const [saving, setSaving] = useState(false)
 	const [userAuthToken, setUserAuthToken] = useState<string>('')
 	const [copied, setCopied] = useState(false)
@@ -28,6 +29,7 @@ export function ConfigPanel({ config, onSave, onClose }: ConfigPanelProps) {
 		setApiKey(config?.apiKey || DEMO_API_KEY)
 		setBaseURL(config?.baseURL || DEMO_BASE_URL)
 		setModel(config?.model || DEMO_MODEL)
+		setLanguage(config?.language)
 	}, [config])
 
 	// Poll for user auth token every second until found
@@ -65,7 +67,7 @@ export function ConfigPanel({ config, onSave, onClose }: ConfigPanelProps) {
 	const handleSave = async () => {
 		setSaving(true)
 		try {
-			await onSave({ apiKey, baseURL, model })
+			await onSave({ apiKey, baseURL, model, language })
 		} finally {
 			setSaving(false)
 		}
@@ -165,6 +167,19 @@ export function ConfigPanel({ config, onSave, onClose }: ConfigPanelProps) {
 				</div>
 			</div>
 
+			<div className="flex flex-col gap-1.5">
+				<label className="text-xs text-muted-foreground">Language</label>
+				<select
+					value={language ?? ''}
+					onChange={(e) => setLanguage((e.target.value || undefined) as LanguagePreference)}
+					className="h-8 text-xs rounded-md border border-input bg-background px-2 cursor-pointer"
+				>
+					<option value="">System</option>
+					<option value="en-US">English</option>
+					<option value="zh-CN">中文</option>
+				</select>
+			</div>
+
 			<div className="flex gap-2 mt-2">
 				<Button variant="outline" onClick={onClose} className="flex-1 h-8 text-xs cursor-pointer">
 					Cancel