diff --git a/src/Client.js b/src/Client.js
index 1173aaa..46e9dd2 100644
--- a/src/Client.js
+++ b/src/Client.js
@@ -214,6 +214,20 @@ class Client extends EventEmitter {
 
         });
 
+        await page.exposeFunction('onMessageAckEvent', (msg, ack) => {
+
+            const message = new Message(this, msg);
+            
+            /**
+             * Emitted when an ack event occurrs on message type.
+             * @event Client#message_ack
+             * @param {Message} message The message that was affected
+             * @param {number} ack The new ACK value
+             */
+            this.emit(Events.MESSAGE_ACK, message, ack);
+
+        });
+
         await page.exposeFunction('onAppStateChangedEvent', (_AppState, state) => {
 
             /**
@@ -239,6 +253,7 @@ class Client extends EventEmitter {
             window.Store.Msg.on('add', window.onAddMessageEvent);
             window.Store.Msg.on('change', window.onChangeMessageEvent);
             window.Store.Msg.on('change:type', window.onChangeMessageTypeEvent);
+            window.Store.Msg.on('change:ack', window.onMessageAckEvent);
             window.Store.Msg.on('remove', window.onRemoveMessageEvent);
             window.Store.AppState.on('change:state', window.onAppStateChangedEvent);
         });
diff --git a/src/util/Constants.js b/src/util/Constants.js
index 55c30ae..738305c 100644
--- a/src/util/Constants.js
+++ b/src/util/Constants.js
@@ -35,9 +35,10 @@ exports.Events = {
     MESSAGE_CREATE: 'message_create',
     MESSAGE_REVOKED_EVERYONE: 'message_revoke_everyone',
     MESSAGE_REVOKED_ME: 'message_revoke_me',
+    MESSAGE_ACK: 'message_ack',
     QR_RECEIVED: 'qr',
     DISCONNECTED: 'disconnected',
-    STATE_CHANGED: 'change_state'
+    STATE_CHANGED: 'change_state',
 };
 
 /**
@@ -89,4 +90,4 @@ exports.WAState = {
     UNLAUNCHED: 'UNLAUNCHED',
     UNPAIRED: 'UNPAIRED',
     UNPAIRED_IDLE: 'UNPAIRED_IDLE'
-};
\ No newline at end of file
+};