diff --git a/client/public/app.js b/client/public/app.js
index c760a5b..c48e921 100644
--- a/client/public/app.js
+++ b/client/public/app.js
@@ -12,6 +12,7 @@ import {
 } from "./data.js";
 import { renderChat } from "./render.js";
 import { initWebSocket } from "./wsModule.js";
+import { primeNotifications } from "./notifications.js";
 
 document.addEventListener("DOMContentLoaded", () => {
   const chat = document.getElementById("chat");
@@ -25,6 +26,7 @@ document.addEventListener("DOMContentLoaded", () => {
 
   chat.style.display = "";
   inputContainer.style.display = "flex";
+  primeNotifications();
 
   const defaultName = "Anon";
   const MAX_NAME_LEN = 15; // server limit is NAME_MAX_LENGTH-1 (15 chars)
diff --git a/client/public/data.js b/client/public/data.js
index 3386284..152af2b 100644
--- a/client/public/data.js
+++ b/client/public/data.js
@@ -1,6 +1,8 @@
 // coms/client/public/data.js
 // Data module: holds the in‐memory threads, notices and reply state
 
+import { notifyNotice } from "./notifications.js";
+
 // Map of all messages and notices by ID (string IDs)
 // Client’s own session ID
 let myId = null;
@@ -139,6 +141,7 @@ function addNotice(content) {
     children: [],
   });
   rootIds.push(id);
+  notifyNotice(content);
 }
 
 /**
diff --git a/client/public/notifications.js b/client/public/notifications.js
new file mode 100644
index 0000000..ec98b2c
--- /dev/null
+++ b/client/public/notifications.js
@@ -0,0 +1,59 @@
+// Simple notification helpers for the chat client.
+
+const APP_NAME = "COMS";
+
+function supportsNotifications() {
+  return typeof Notification !== "undefined";
+}
+
+function stripHtml(input) {
+  const div = document.createElement("div");
+  div.innerHTML = input;
+  return div.textContent || div.innerText || "";
+}
+
+/**
+ * Ask for permission if not already granted/denied.
+ */
+function primeNotifications() {
+  if (!supportsNotifications()) return;
+  if (Notification.permission === "default") {
+    Notification.requestPermission();
+  }
+}
+
+function showNotification(title, body) {
+  if (!supportsNotifications()) return;
+  const options = { body };
+  if (Notification.permission === "granted") {
+    new Notification(title, options);
+  } else if (Notification.permission === "default") {
+    Notification.requestPermission().then((perm) => {
+      if (perm === "granted") new Notification(title, options);
+    });
+  }
+}
+
+/**
+ * Notify the user of a system notice.
+ * @param {string} content - HTML or text content of the notice.
+ */
+function notifyNotice(content) {
+  const text = stripHtml(content);
+  if (!text) return;
+  showNotification(`${APP_NAME} notice`, text);
+}
+
+/**
+ * Notify the user that someone replied directly to their thread.
+ * @param {string} authorName
+ * @param {string} content
+ */
+function notifyDirectReply(authorName, content) {
+  const text = stripHtml(content);
+  if (!text) return;
+  const name = authorName || "Anon";
+  showNotification(`${name} replied to your thread`, text);
+}
+
+export { primeNotifications, notifyNotice, notifyDirectReply };
diff --git a/client/public/wsModule.js b/client/public/wsModule.js
index 3dedbe2..27e4025 100644
--- a/client/public/wsModule.js
+++ b/client/public/wsModule.js
@@ -13,12 +13,15 @@ import {
   updateUser,
   getGroupedUsers,
   setMyId,
+  getMyId,
+  getThreads,
   clearData,
   users,
   setFocused,
   setReplyTo,
 } from "./data.js";
 import { renderChat } from "./render.js";
+import { notifyDirectReply } from "./notifications.js";
 
 /**
  * Initialize WebSocket connection and wire up event handlers.
@@ -132,6 +135,23 @@ export function initWebSocket(
               ? null
               : String(parent),
         });
+
+        // Notify when someone else replies directly to one of my root messages.
+        const myId = getMyId();
+        const parentId =
+          parent === null || parent === undefined || parent === "-1"
+            ? null
+            : String(parent);
+        if (myId && parentId && author?.id && String(author.id) !== myId) {
+          const parentMsg = getThreads().get(parentId);
+          if (
+            parentMsg &&
+            parentMsg.parent === null &&
+            parentMsg.authorId === myId
+          ) {
+            notifyDirectReply(username, content);
+          }
+        }
         break;
       }
       case "msg_ack": {