diff --git a/README.md b/README.md
index 574bb5d..6f7673e 100644
--- a/README.md
+++ b/README.md
@@ -400,6 +400,7 @@ Request body must has a notifications array. The following is a parameter table
 
 | name           | type             | description                                                                                      | required | note |
 |----------------|------------------|--------------------------------------------------------------------------------------------------|----------|------|
+| subtitle       | string           | Apple Watch & Safari display this string as part of the notification interface.                  | -        |      |
 | action         | string           | The label of the action button. This one is required for Safari Push Notifications.              | -        |      |
 | action-loc-key | string           | If a string is specified, the system displays an alert that includes the Close and View buttons. | -        |      |
 | launch-image   | string           | The filename of an image file in the app bundle, with or without the filename extension.         | -        |      |
diff --git a/gorush/notification.go b/gorush/notification.go
index 6bd7847..821965b 100644
--- a/gorush/notification.go
+++ b/gorush/notification.go
@@ -39,6 +39,7 @@ type Alert struct {
 	LocArgs      []string `json:"loc-args,omitempty"`
 	LocKey       string   `json:"loc-key,omitempty"`
 	Title        string   `json:"title,omitempty"`
+	Subtitle     string   `json:"subtitle,omitempty"`
 	TitleLocArgs []string `json:"title-loc-args,omitempty"`
 	TitleLocKey  string   `json:"title-loc-key,omitempty"`
 }
@@ -238,6 +239,11 @@ func iosAlertDictionary(payload *payload.Payload, req PushNotification) *payload
 		payload.AlertTitle(req.Title)
 	}
 
+	// Apple Watch & Safari display this string as part of the notification interface.
+	if len(req.Alert.Subtitle) > 0 {
+		payload.AlertSubtitle(req.Alert.Subtitle)
+	}
+
 	if len(req.Alert.TitleLocKey) > 0 {
 		payload.AlertTitleLocKey(req.Alert.TitleLocKey)
 	}
diff --git a/gorush/notification_test.go b/gorush/notification_test.go
index 5f8f1de..9c4524f 100644
--- a/gorush/notification_test.go
+++ b/gorush/notification_test.go
@@ -132,6 +132,7 @@ func TestIOSAlertNotificationStructure(t *testing.T) {
 			LaunchImage:  test,
 			LocArgs:      []string{"a", "b"},
 			LocKey:       test,
+			Subtitle:     test,
 			TitleLocArgs: []string{"a", "b"},
 			TitleLocKey:  test,
 		},
@@ -153,6 +154,7 @@ func TestIOSAlertNotificationStructure(t *testing.T) {
 	launchImage, _ := jsonparser.GetString(data, "aps", "alert", "launch-image")
 	locKey, _ := jsonparser.GetString(data, "aps", "alert", "loc-key")
 	title, _ := jsonparser.GetString(data, "aps", "alert", "title")
+	subtitle, _ := jsonparser.GetString(data, "aps", "alert", "subtitle")
 	titleLocKey, _ := jsonparser.GetString(data, "aps", "alert", "title-loc-key")
 	aps := dat["aps"].(map[string]interface{})
 	alert := aps["alert"].(map[string]interface{})
@@ -165,6 +167,7 @@ func TestIOSAlertNotificationStructure(t *testing.T) {
 	assert.Equal(t, test, launchImage)
 	assert.Equal(t, test, locKey)
 	assert.Equal(t, test, title)
+	assert.Equal(t, test, subtitle)
 	assert.Equal(t, test, titleLocKey)
 	assert.Contains(t, titleLocArgs, "a")
 	assert.Contains(t, titleLocArgs, "b")