diff --git a/app/Tester/Tester.cpp b/app/Tester/Tester.cpp
index 70cb574..5dcf350 100644
--- a/app/Tester/Tester.cpp
+++ b/app/Tester/Tester.cpp
@@ -18,7 +18,8 @@ VOID CALLBACK notification(
     PVIGEM_TARGET Target,
     UCHAR LargeMotor,
     UCHAR SmallMotor,
-    UCHAR LedNumber
+    UCHAR LedNumber,
+    LPVOID UserData
 )
 {
     m.lock();
@@ -46,7 +47,7 @@ int main()
 
 	ret = vigem_target_add(client, x360);
 
-	ret = vigem_target_x360_register_notification(client, x360, &notification);
+	ret = vigem_target_x360_register_notification(client, x360, &notification, nullptr);
 #endif
 	
 	const auto ds4 = vigem_target_ds4_alloc();
diff --git a/include/ViGEm/Client.h b/include/ViGEm/Client.h
index 722f3f4..3d36283 100644
--- a/include/ViGEm/Client.h
+++ b/include/ViGEm/Client.h
@@ -113,7 +113,8 @@ extern "C" {
             PVIGEM_TARGET Target,
             UCHAR LargeMotor,
             UCHAR SmallMotor,
-            UCHAR LedNumber
+            UCHAR LedNumber,
+            LPVOID UserData
         );
 
     typedef EVT_VIGEM_X360_NOTIFICATION *PFN_VIGEM_X360_NOTIFICATION;
@@ -126,7 +127,8 @@ extern "C" {
             PVIGEM_TARGET Target,
             UCHAR LargeMotor,
             UCHAR SmallMotor,
-            DS4_LIGHTBAR_COLOR LightbarColor
+            DS4_LIGHTBAR_COLOR LightbarColor,
+            LPVOID UserData
         );
 
     typedef EVT_VIGEM_DS4_NOTIFICATION *PFN_VIGEM_DS4_NOTIFICATION;
@@ -291,10 +293,11 @@ extern "C" {
      * \param   vigem           The driver connection object.
      * \param   target          The target device object.
      * \param   notification    The notification callback.
+     * \param   userData        The user data passed to the notification callback.
      *
      * \return  A VIGEM_ERROR.
      */
-    VIGEM_API VIGEM_ERROR vigem_target_x360_register_notification(PVIGEM_CLIENT vigem, PVIGEM_TARGET target, PFN_VIGEM_X360_NOTIFICATION notification);
+    VIGEM_API VIGEM_ERROR vigem_target_x360_register_notification(PVIGEM_CLIENT vigem, PVIGEM_TARGET target, PFN_VIGEM_X360_NOTIFICATION notification, LPVOID userData);
 
     /**
      * \fn  VIGEM_ERROR vigem_target_ds4_register_notification(PVIGEM_CLIENT vigem, PVIGEM_TARGET target, PVIGEM_DS4_NOTIFICATION notification);
@@ -309,10 +312,11 @@ extern "C" {
      * \param   vigem           The driver connection object.
      * \param   target          The target device object.
      * \param   notification    The notification callback.
+     * \param   userData        The user data passed to the notification callback.
      *
      * \return  A VIGEM_ERROR.
      */
-    VIGEM_API VIGEM_ERROR vigem_target_ds4_register_notification(PVIGEM_CLIENT vigem, PVIGEM_TARGET target, PFN_VIGEM_DS4_NOTIFICATION notification);
+    VIGEM_API VIGEM_ERROR vigem_target_ds4_register_notification(PVIGEM_CLIENT vigem, PVIGEM_TARGET target, PFN_VIGEM_DS4_NOTIFICATION notification, LPVOID userData);
 
     /**
      * \fn  void vigem_target_x360_unregister_notification(PVIGEM_TARGET target);
diff --git a/src/Internal.h b/src/Internal.h
index d8f52ea..888a5a7 100644
--- a/src/Internal.h
+++ b/src/Internal.h
@@ -65,6 +65,7 @@ typedef struct _VIGEM_TARGET_T
     USHORT ProductId;
     VIGEM_TARGET_TYPE Type;
     FARPROC Notification;
+    LPVOID NotificationUserData;
 
 	bool closingNotificationThreads;
 	HANDLE cancelNotificationThreadEvent;
diff --git a/src/ViGEmClient.cpp b/src/ViGEmClient.cpp
index e4d0b88..18e8bd8 100644
--- a/src/ViGEmClient.cpp
+++ b/src/ViGEmClient.cpp
@@ -106,10 +106,11 @@ public:
 	void ProcessNotificationRequest(PVIGEM_CLIENT client, PVIGEM_TARGET target) override
 	{
 		if(target->Notification != nullptr)
-			PFN_VIGEM_X360_NOTIFICATION(target->Notification)(client, target, 
+			PFN_VIGEM_X360_NOTIFICATION(target->Notification)(client, target,
 				((PXUSB_REQUEST_NOTIFICATION)lpPayloadBuffer)->LargeMotor, 
 				((PXUSB_REQUEST_NOTIFICATION)lpPayloadBuffer)->SmallMotor,
-				((PXUSB_REQUEST_NOTIFICATION)lpPayloadBuffer)->LedNumber
+				((PXUSB_REQUEST_NOTIFICATION)lpPayloadBuffer)->LedNumber,
+				target->NotificationUserData
 			);
 	}
 };
@@ -129,7 +130,8 @@ public:
 			PFN_VIGEM_DS4_NOTIFICATION(target->Notification)(client, target,
 				((PDS4_REQUEST_NOTIFICATION)lpPayloadBuffer)->Report.LargeMotor,
 				((PDS4_REQUEST_NOTIFICATION)lpPayloadBuffer)->Report.SmallMotor,
-				((PDS4_REQUEST_NOTIFICATION)lpPayloadBuffer)->Report.LightbarColor
+				((PDS4_REQUEST_NOTIFICATION)lpPayloadBuffer)->Report.LightbarColor,
+				target->NotificationUserData
 			);
 	}
 };
@@ -658,7 +660,8 @@ void vigem_notification_thread_worker(
 VIGEM_ERROR vigem_target_x360_register_notification(
     PVIGEM_CLIENT vigem,
     PVIGEM_TARGET target,
-    PFN_VIGEM_X360_NOTIFICATION notification
+    PFN_VIGEM_X360_NOTIFICATION notification,
+    LPVOID userData
 )
 {
     if (!vigem)
@@ -677,6 +680,7 @@ VIGEM_ERROR vigem_target_x360_register_notification(
         return VIGEM_ERROR_CALLBACK_ALREADY_REGISTERED;
 
     target->Notification = reinterpret_cast<FARPROC>(notification);
+    target->NotificationUserData = userData;
 
 	if (target->cancelNotificationThreadEvent == 0)
 		target->cancelNotificationThreadEvent = CreateEvent(nullptr, TRUE, FALSE, nullptr);
@@ -704,7 +708,8 @@ VIGEM_ERROR vigem_target_x360_register_notification(
 VIGEM_ERROR vigem_target_ds4_register_notification(
     PVIGEM_CLIENT vigem,
     PVIGEM_TARGET target,
-    PFN_VIGEM_DS4_NOTIFICATION notification
+    PFN_VIGEM_DS4_NOTIFICATION notification,
+    LPVOID userData
 )
 {
     if (!vigem)
@@ -723,6 +728,7 @@ VIGEM_ERROR vigem_target_ds4_register_notification(
         return VIGEM_ERROR_CALLBACK_ALREADY_REGISTERED;
 
     target->Notification = reinterpret_cast<FARPROC>(notification);
+    target->NotificationUserData = userData;
 
 	if (target->cancelNotificationThreadEvent == 0)
 		target->cancelNotificationThreadEvent = CreateEvent(nullptr, TRUE, FALSE, nullptr);
@@ -767,6 +773,7 @@ void vigem_target_x360_unregister_notification(PVIGEM_TARGET target)
 	}
 
 	target->Notification = nullptr;
+	target->NotificationUserData = nullptr;
 }
 
 void vigem_target_ds4_unregister_notification(PVIGEM_TARGET target)