diff --git a/client/app.go b/client/app.go
index 79471f5..7399751 100644
--- a/client/app.go
+++ b/client/app.go
@@ -973,17 +973,20 @@ func (a *App) connectWS() {
 			case "stop_webcam_stream":
 				runtime.EventsEmit(a.ctx, "stop_webcam_stream")
 			case "chat:message":
-				if staffVal, ok := msg.Data["staffId"].(float64); ok {
-					a.mu.Lock()
-					a.replyStaffID = uint(staffVal)
-					a.chatUnread++
-					unread := a.chatUnread
-					a.mu.Unlock()
-					runtime.EventsEmit(a.ctx, "chat:notify", map[string]any{
-						"unread":  unread,
-						"preview": msg.Data["body"],
-						"from":    msg.Data["staffName"],
-					})
+				senderRole, _ := msg.Data["senderRole"].(string)
+				if senderRole == "staff" {
+					if staffVal, ok := msg.Data["staffId"].(float64); ok {
+						a.mu.Lock()
+						a.replyStaffID = uint(staffVal)
+						a.chatUnread++
+						unread := a.chatUnread
+						a.mu.Unlock()
+						runtime.EventsEmit(a.ctx, "chat:notify", map[string]any{
+							"unread":  unread,
+							"preview": msg.Data["body"],
+							"from":    msg.Data["staffName"],
+						})
+					}
 				}
 				runtime.EventsEmit(a.ctx, "chat:message", msg.Data)
 			}
diff --git a/client/frontend/src/main.js b/client/frontend/src/main.js
index 5cd42f7..0a69052 100644
--- a/client/frontend/src/main.js
+++ b/client/frontend/src/main.js
@@ -27,6 +27,34 @@ let chatOpen = false;
 let chatMessages = [];
 let chatConversations = [];
 let activeStaffId = 0;
+let chatAudioCtx = null;
+
+function playChatSound() {
+  try {
+    const Ctx = window.AudioContext || window.webkitAudioContext;
+    if (!chatAudioCtx) chatAudioCtx = new Ctx();
+    const ctx = chatAudioCtx;
+    if (ctx.state === 'suspended') ctx.resume();
+    const tone = (freq, start, dur) => {
+      const osc = ctx.createOscillator();
+      const gain = ctx.createGain();
+      osc.type = 'sine';
+      osc.frequency.value = freq;
+      gain.gain.setValueAtTime(0.0001, start);
+      gain.gain.exponentialRampToValueAtTime(0.15, start + 0.02);
+      gain.gain.exponentialRampToValueAtTime(0.0001, start + dur);
+      osc.connect(gain);
+      gain.connect(ctx.destination);
+      osc.start(start);
+      osc.stop(start + dur + 0.02);
+    };
+    const t = ctx.currentTime;
+    tone(880, t, 0.12);
+    tone(1174, t + 0.14, 0.14);
+  } catch {
+    /* ignore */
+  }
+}
 
 // Quản lý webcam
 let webcamStream = null;
@@ -51,14 +79,18 @@ function init() {
 
   window.runtime.EventsOn('start_webcam_stream', startWebcam);
   window.runtime.EventsOn('stop_webcam_stream', stopWebcam);
-  window.runtime.EventsOn('chat:message', () => {
+  window.runtime.EventsOn('chat:message', (data) => {
     updateChatBadge();
     loadChatConversations().catch(console.error);
     if (chatOpen && activeStaffId) loadChatMessages(activeStaffId).catch(console.error);
+    if (data?.senderRole === 'staff') {
+      playChatSound();
+    }
   });
   window.runtime.EventsOn('chat:notify', (data) => {
     updateChatBadge();
     showChatToast(data);
+    playChatSound();
   });
   checkLogin();
 }
diff --git a/management/src/App.tsx b/management/src/App.tsx
index 487a83b..c5e331b 100644
--- a/management/src/App.tsx
+++ b/management/src/App.tsx
@@ -6,6 +6,7 @@ import { LearningTab } from './components/LearningTab';
 import { NetworkTab } from './components/NetworkTab';
 import { AccountsTab } from './components/AccountsTab';
 import { ChatWidget } from './components/ChatWidget';
+import { StaffChatSocket } from './hooks/useStaffChatSocket';
 import { ClassWorkspace } from './components/ClassWorkspace';
 import { NavHistoryBar, useRoute } from './components/NavHistoryBar';
 import { goBack, navigate, parseRoute, pushNav, TAB_LABELS, type TabId } from './navigation';
@@ -186,6 +187,7 @@ function App() {
           )}
         </div>
       </main>
+      <StaffChatSocket />
       <ChatWidget />
     </>
   );
diff --git a/management/src/api.ts b/management/src/api.ts
index 282f437..08859e4 100644
--- a/management/src/api.ts
+++ b/management/src/api.ts
@@ -113,6 +113,7 @@ export interface ChatStudent {
 export interface ChatMessage {
   id: number;
   staffId: number;
+  targetStaffId?: number;
   studentRkId: number;
   senderRole: 'staff' | 'student';
   body: string;
diff --git a/management/src/components/ChatWidget.tsx b/management/src/components/ChatWidget.tsx
index 75863fd..c37da21 100644
--- a/management/src/components/ChatWidget.tsx
+++ b/management/src/components/ChatWidget.tsx
@@ -2,6 +2,7 @@ import { useCallback, useEffect, useRef, useState } from 'react';
 import { createPortal } from 'react-dom';
 import { apiChat, type ChatConversation, type ChatMessage, type ChatStudent } from '../api';
 import { useAuth } from '../auth/AuthContext';
+import { onStaffChatMessage, playChatSound } from '../hooks/useStaffChatSocket';
 
 export function ChatWidget() {
   const { staff } = useAuth();
@@ -14,12 +15,13 @@ export function ChatWidget() {
   const [draft, setDraft] = useState('');
   const [sending, setSending] = useState(false);
   const [pickerOpen, setPickerOpen] = useState(false);
+  const [toast, setToast] = useState<{ title: string; body: string } | null>(null);
   const listRef = useRef<HTMLDivElement>(null);
   const activeRef = useRef<ChatStudent | null>(null);
+  const openRef = useRef(false);
 
-  useEffect(() => {
-    activeRef.current = active;
-  }, [active]);
+  useEffect(() => { activeRef.current = active; }, [active]);
+  useEffect(() => { openRef.current = open; }, [open]);
 
   const scrollBottom = () => {
     requestAnimationFrame(() => {
@@ -32,6 +34,7 @@ export function ChatWidget() {
   const loadConversations = useCallback(async () => {
     const res = await apiChat.listConversations();
     setConversations(res.data);
+    return res.data;
   }, []);
 
   const loadMessages = useCallback(async (studentRkId: number) => {
@@ -46,6 +49,46 @@ export function ChatWidget() {
     setStudents(res.data);
   }, []);
 
+  const showToast = (title: string, body: string) => {
+    setToast({ title, body });
+    setTimeout(() => setToast(null), 4500);
+  };
+
+  const handleIncoming = useCallback((msg: ChatMessage) => {
+    const studentId = Number(msg.studentRkId);
+    const current = activeRef.current;
+
+    void loadConversations();
+
+    if (msg.senderRole === 'student') {
+      playChatSound();
+      const preview = msg.body?.slice(0, 80) || 'Tin nhắn mới';
+      if (!openRef.current || !current || Number(current.studentRkId) !== studentId) {
+        showToast('Sinh viên nhắn tin', preview);
+      }
+    }
+
+    if (current && Number(current.studentRkId) === studentId) {
+      setMessages((prev) => {
+        if (prev.some((m) => m.id === msg.id)) return prev;
+        return [...prev, msg];
+      });
+      scrollBottom();
+    }
+  }, [loadConversations]);
+
+  useEffect(() => {
+    const off = onStaffChatMessage(handleIncoming);
+    return () => { off(); };
+  }, [handleIncoming]);
+
+  useEffect(() => {
+    if (!staff?.id) return;
+    loadConversations().catch(console.error);
+    const t = setInterval(() => loadConversations().catch(console.error), 5000);
+    return () => clearInterval(t);
+  }, [staff?.id, loadConversations]);
+
   const pickStudent = async (s: ChatStudent) => {
     setActive(s);
     setPickerOpen(false);
@@ -69,32 +112,6 @@ export function ChatWidget() {
     searchStudents('').catch(console.error);
   }, [open, staff?.id, loadConversations, searchStudents]);
 
-  useEffect(() => {
-    if (!staff?.id) return;
-    const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
-    const wsUrl = `${protocol}//${window.location.hostname}:8080/ws?role=teacher&staffId=${staff.id}`;
-    const ws = new WebSocket(wsUrl);
-    ws.onmessage = (ev) => {
-      try {
-        const payload = JSON.parse(ev.data);
-        if (payload.event !== 'chat:message') return;
-        const msg = payload.data as ChatMessage;
-        loadConversations().catch(console.error);
-        const current = activeRef.current;
-        if (current && msg.studentRkId === current.studentRkId) {
-          setMessages((prev) => {
-            if (prev.some((m) => m.id === msg.id)) return prev;
-            return [...prev, msg];
-          });
-          scrollBottom();
-        }
-      } catch {
-        /* ignore */
-      }
-    };
-    return () => ws.close();
-  }, [staff?.id, loadConversations]);
-
   const send = async () => {
     if (!active || !draft.trim()) return;
     setSending(true);
@@ -113,6 +130,12 @@ export function ChatWidget() {
 
   const dock = (
     <div className="chat-dock">
+      {toast && (
+        <div className="chat-toast" role="status">
+          <strong>{toast.title}</strong>
+          <span>{toast.body}</span>
+        </div>
+      )}
       {!open ? (
         <button type="button" className="chat-fab" onClick={() => setOpen(true)} title="Tin nhắn">
           💬
diff --git a/management/src/hooks/useStaffChatSocket.ts b/management/src/hooks/useStaffChatSocket.ts
new file mode 100644
index 0000000..53d2470
--- /dev/null
+++ b/management/src/hooks/useStaffChatSocket.ts
@@ -0,0 +1,71 @@
+import { useCallback, useEffect, useRef } from 'react';
+import { type ChatMessage } from '../api';
+import { useAuth } from '../auth/AuthContext';
+import { playChatSound } from '../utils/notifySound';
+
+type ChatIncomingHandler = (msg: ChatMessage) => void;
+
+const handlers = new Set<ChatIncomingHandler>();
+
+export function onStaffChatMessage(handler: ChatIncomingHandler): () => void {
+  handlers.add(handler);
+  return () => { handlers.delete(handler); };
+}
+
+/** WebSocket luôn bật khi đã login — nhận tin sinh viên realtime */
+export function StaffChatSocket() {
+  const { staff, token } = useAuth();
+  const staffIdRef = useRef(0);
+
+  useEffect(() => {
+    staffIdRef.current = staff?.id ?? 0;
+  }, [staff?.id]);
+
+  const dispatch = useCallback((msg: ChatMessage) => {
+    handlers.forEach((h) => h(msg));
+  }, []);
+
+  useEffect(() => {
+    if (!token || !staff?.id) return;
+
+    const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
+    const wsUrl = `${protocol}//${window.location.hostname}:8080/ws?role=teacher&staffId=${staff.id}`;
+    let ws: WebSocket | null = null;
+    let retryTimer: ReturnType<typeof setTimeout> | null = null;
+    let closed = false;
+
+    const connect = () => {
+      if (closed) return;
+      ws = new WebSocket(wsUrl);
+      ws.onmessage = (ev) => {
+        try {
+          const payload = JSON.parse(ev.data);
+          if (payload.event !== 'chat:message') return;
+          const msg = payload.data as ChatMessage;
+          const targetStaff = Number(msg.targetStaffId ?? msg.staffId ?? 0);
+          if (targetStaff > 0 && targetStaff !== staffIdRef.current) return;
+          dispatch(msg);
+        } catch {
+          /* ignore */
+        }
+      };
+      ws.onclose = () => {
+        if (!closed) {
+          retryTimer = setTimeout(connect, 3000);
+        }
+      };
+    };
+
+    connect();
+
+    return () => {
+      closed = true;
+      if (retryTimer) clearTimeout(retryTimer);
+      ws?.close();
+    };
+  }, [token, staff?.id, dispatch]);
+
+  return null;
+}
+
+export { playChatSound };
diff --git a/management/src/index.css b/management/src/index.css
index 9c2ebed..dc18732 100644
--- a/management/src/index.css
+++ b/management/src/index.css
@@ -3371,6 +3371,33 @@ input:checked + .slider:before {
   font-family: var(--font-sans);
 }
 
+.chat-toast {
+  position: absolute;
+  right: 0;
+  bottom: 72px;
+  width: 280px;
+  padding: 0.7rem 0.85rem;
+  border-radius: 10px;
+  background: #1e293b;
+  color: #fff;
+  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.25);
+  display: flex;
+  flex-direction: column;
+  gap: 0.25rem;
+  font-size: 0.82rem;
+  animation: chat-toast-in 0.25s ease;
+}
+
+.chat-toast strong {
+  font-size: 0.78rem;
+  color: #93c5fd;
+}
+
+@keyframes chat-toast-in {
+  from { opacity: 0; transform: translateY(8px); }
+  to { opacity: 1; transform: translateY(0); }
+}
+
 .chat-fab {
   position: relative;
   width: 56px;
diff --git a/management/src/utils/notifySound.ts b/management/src/utils/notifySound.ts
new file mode 100644
index 0000000..59f0d6c
--- /dev/null
+++ b/management/src/utils/notifySound.ts
@@ -0,0 +1,37 @@
+let audioCtx: AudioContext | null = null;
+
+function getAudioCtx(): AudioContext | null {
+  if (audioCtx) return audioCtx;
+  try {
+    const Ctx = window.AudioContext || (window as unknown as { webkitAudioContext: typeof AudioContext }).webkitAudioContext;
+    audioCtx = new Ctx();
+    return audioCtx;
+  } catch {
+    return null;
+  }
+}
+
+/** Short two-tone ping for chat notifications */
+export function playChatSound() {
+  const ctx = getAudioCtx();
+  if (!ctx) return;
+  if (ctx.state === 'suspended') {
+    void ctx.resume();
+  }
+  const playTone = (freq: number, start: number, duration: number) => {
+    const osc = ctx.createOscillator();
+    const gain = ctx.createGain();
+    osc.type = 'sine';
+    osc.frequency.value = freq;
+    gain.gain.setValueAtTime(0.0001, start);
+    gain.gain.exponentialRampToValueAtTime(0.12, start + 0.02);
+    gain.gain.exponentialRampToValueAtTime(0.0001, start + duration);
+    osc.connect(gain);
+    gain.connect(ctx.destination);
+    osc.start(start);
+    osc.stop(start + duration + 0.02);
+  };
+  const t = ctx.currentTime;
+  playTone(880, t, 0.12);
+  playTone(1174, t + 0.14, 0.14);
+}
diff --git a/server/internal/handlers/handlers_chat.go b/server/internal/handlers/handlers_chat.go
index da03a76..79c6103 100644
--- a/server/internal/handlers/handlers_chat.go
+++ b/server/internal/handlers/handlers_chat.go
@@ -13,8 +13,8 @@ import (
 	"gorm.io/gorm"
 )
 
-func chatMessageDTO(m models.ChatMessage, staffName string) fiber.Map {
-	return fiber.Map{
+func chatMessageDTO(m models.ChatMessage, staffName string) map[string]any {
+	return map[string]any{
 		"id":          m.ID,
 		"staffId":     m.StaffID,
 		"studentRkId": m.StudentRkID,
diff --git a/server/internal/websocket/websocket.go b/server/internal/websocket/websocket.go
index e0f2c71..ff846a5 100644
--- a/server/internal/websocket/websocket.go
+++ b/server/internal/websocket/websocket.go
@@ -58,15 +58,15 @@ func (h *WsHub) PushChatToStudent(studentRkID int64, data map[string]any) {
 }
 
 func (h *WsHub) PushChatToStaff(staffID uint, data map[string]any) {
-	h.mu.RLock()
-	addrs := append([]string(nil), h.teachersByStaff[staffID]...)
-	h.mu.RUnlock()
+	if data == nil {
+		data = map[string]any{}
+	}
+	data["targetStaffId"] = staffID
 	msg := SocketMsg{Event: "chat:message", Data: data}
-	for _, addr := range addrs {
-		h.mu.RLock()
-		t, found := h.teachers[addr]
-		h.mu.RUnlock()
-		if found && t != nil {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	for _, t := range h.teachers {
+		if t != nil && t.Role == "teacher" {
 			_ = t.Conn.WriteJSON(msg)
 		}
 	}