diff --git a/src/mibew/libs/classes/Mibew/EventDispatcher/Events.php b/src/mibew/libs/classes/Mibew/EventDispatcher/Events.php
index ac0f0e41..40295809 100644
--- a/src/mibew/libs/classes/Mibew/EventDispatcher/Events.php
+++ b/src/mibew/libs/classes/Mibew/EventDispatcher/Events.php
@@ -60,6 +60,16 @@ final class Events
      */
     const INVITATION_CREATE = 'invitationCreate';
 
+    /**
+     * An invitation is accepted.
+     *
+     * This event is triggered after an invitation has been accepted by a
+     * visitor. An associative array with the following items is passed to the
+     * event handlers:
+     *  - "invitation": an instance of {@link \Mibew\Thread} class.
+     */
+    const INVITATION_ACCEPT = 'invitationAccept';
+
     /**
      * An operator cannot be authenticated.
      *
diff --git a/src/mibew/libs/invitation.php b/src/mibew/libs/invitation.php
index 12dab322..5b8bf3c2 100644
--- a/src/mibew/libs/invitation.php
+++ b/src/mibew/libs/invitation.php
@@ -151,6 +151,8 @@ function invitation_invite($visitor_id, $operator)
 /**
  * Invitation was accepted by visitor
  *
+ * Triggers {@link \Mibew\EventDispatcher\Events::INVITATION_ACCEPT} event.
+ *
  * @param int $visitor_id ID of the visitor who accept invitation
  * @return Thread|boolean Thread object or boolean false on failure
  */
@@ -195,6 +197,9 @@ function invitation_accept($visitor_id)
         array(':visitor_id' => $visitor_id)
     );
 
+    $args = array('invitation' => $thread);
+    EventDispatcher::getInstance()->triggerEvent(Events::INVITATION_ACCEPT, $args);
+
     return $thread;
 }