diff --git a/src/main/java/com/google/firebase/messaging/ApsAlert.java b/src/main/java/com/google/firebase/messaging/ApsAlert.java
index 6f7e249f3..2efa94433 100644
--- a/src/main/java/com/google/firebase/messaging/ApsAlert.java
+++ b/src/main/java/com/google/firebase/messaging/ApsAlert.java
@@ -34,6 +34,9 @@ public class ApsAlert {
   @Key("title")
   private final String title;
 
+  @Key("subtitle")
+  private final String subtitle;
+
   @Key("body")
   private final String body;
 
@@ -49,6 +52,12 @@ public class ApsAlert {
   @Key("title-loc-args")
   private final List<String> titleLocArgs;
 
+  @Key("subtitle-loc-key")
+  private final String subtitleLocKey;
+
+  @Key("subtitle-loc-args")
+  private final List<String> subtitleLocArgs;
+
   @Key("action-loc-key")
   private final String actionLocKey;
 
@@ -57,6 +66,7 @@ public class ApsAlert {
 
   private ApsAlert(Builder builder) {
     this.title = builder.title;
+    this.subtitle = builder.subtitle;
     this.body = builder.body;
     this.actionLocKey = builder.actionLocKey;
     this.locKey = builder.locKey;
@@ -76,6 +86,14 @@ private ApsAlert(Builder builder) {
     } else {
       this.titleLocArgs = null;
     }
+    this.subtitleLocKey = builder.subtitleLocKey;
+    if (!builder.subtitleLocArgs.isEmpty()) {
+      checkArgument(!Strings.isNullOrEmpty(builder.subtitleLocKey),
+          "subtitleLocKey is required when specifying subtitleLocArgs");
+      this.subtitleLocArgs = ImmutableList.copyOf(builder.subtitleLocArgs);
+    } else {
+      this.subtitleLocArgs = null;
+    }
     this.launchImage = builder.launchImage;
   }
 
@@ -91,11 +109,14 @@ public static Builder builder() {
   public static class Builder {
 
     private String title;
+    private String subtitle;
     private String body;
     private String locKey;
     private List<String> locArgs = new ArrayList<>();
     private String titleLocKey;
     private List<String> titleLocArgs = new ArrayList<>();
+    private String subtitleLocKey;
+    private List<String> subtitleLocArgs = new ArrayList<>();
     private String actionLocKey;
     private String launchImage;
 
@@ -113,6 +134,17 @@ public Builder setTitle(String title) {
       return this;
     }
 
+    /**
+     * Sets the subtitle of the alert.
+     *
+     * @param subtitle Subtitle of the notification.
+     * @return This builder.
+     */
+    public Builder setSubtitle(String subtitle) {
+      this.subtitle = subtitle;
+      return this;
+    }
+
     /**
      * Sets the body of the alert. When provided, overrides the body sent
      * via {@link Notification}.
@@ -209,6 +241,42 @@ public Builder addAllTitleLocArgs(@NonNull List<String> args) {
       return this;
     }
 
+    /**
+     * Sets the key of the subtitle string in the app's string resources to use to localize 
+     * the subtitle text.
+     *
+     * @param subtitleLocKey Resource key string.
+     * @return This builder.
+     */
+    public Builder setSubtitleLocalizationKey(String subtitleLocKey) {
+      this.subtitleLocKey = subtitleLocKey;
+      return this;
+    }
+
+    /**
+     * Adds a resource key string that will be used in place of the format specifiers in
+     * {@code subtitleLocKey}.
+     *
+     * @param arg Resource key string.
+     * @return This builder.
+     */
+    public Builder addSubtitleLocalizationArg(@NonNull String arg) {
+      this.subtitleLocArgs.add(arg);
+      return this;
+    }
+
+    /**
+     * Adds a list of resource keys that will be used in place of the format specifiers in
+     * {@code subtitleLocKey}.
+     *
+     * @param args List of resource key strings.
+     * @return This builder.
+     */
+    public Builder addAllSubtitleLocArgs(@NonNull List<String> args) {
+      this.subtitleLocArgs.addAll(args);
+      return this;
+    }
+
     /**
      * Sets the launch image for the notification action.
      *
diff --git a/src/test/java/com/google/firebase/messaging/FirebaseMessagingTest.java b/src/test/java/com/google/firebase/messaging/FirebaseMessagingTest.java
index 4b51513be..1ad74ac33 100644
--- a/src/test/java/com/google/firebase/messaging/FirebaseMessagingTest.java
+++ b/src/test/java/com/google/firebase/messaging/FirebaseMessagingTest.java
@@ -644,6 +644,7 @@ private static Map<Message, Map<String, Object>> buildTestMessages() {
                     .setBadge(42)
                     .setAlert(ApsAlert.builder()
                         .setTitle("test-title")
+                        .setSubtitle("test-subtitle")
                         .setBody("test-body")
                         .build())
                     .build())
@@ -657,7 +658,8 @@ private static Map<Message, Map<String, Object>> buildTestMessages() {
                 "payload", ImmutableMap.of("k1", "v1", "k2", true,
                     "aps", ImmutableMap.<String, Object>of("badge", new BigDecimal(42),
                         "alert", ImmutableMap.<String, Object>of(
-                            "title", "test-title", "body", "test-body"))))
+                            "title", "test-title", "subtitle", "test-subtitle", 
+                            "body", "test-body"))))
         ));
 
     // Webpush message (no notification)
diff --git a/src/test/java/com/google/firebase/messaging/MessageTest.java b/src/test/java/com/google/firebase/messaging/MessageTest.java
index 3313f2bb3..b6025c0bb 100644
--- a/src/test/java/com/google/firebase/messaging/MessageTest.java
+++ b/src/test/java/com/google/firebase/messaging/MessageTest.java
@@ -393,14 +393,18 @@ public void testApnsMessageWithPayloadAndAps() throws IOException {
             .setAps(Aps.builder()
                 .setAlert(ApsAlert.builder()
                     .setTitle("test-title")
+                    .setSubtitle("test-subtitle")
                     .setBody("test-body")
                     .setLocalizationKey("test-loc-key")
                     .setActionLocalizationKey("test-action-loc-key")
                     .setTitleLocalizationKey("test-title-loc-key")
+                    .setSubtitleLocalizationKey("test-subtitle-loc-key")
                     .addLocalizationArg("arg1")
                     .addAllLocalizationArgs(ImmutableList.of("arg2", "arg3"))
                     .addTitleLocalizationArg("arg4")
                     .addAllTitleLocArgs(ImmutableList.of("arg5", "arg6"))
+                    .addSubtitleLocalizationArg("arg7")
+                    .addAllSubtitleLocArgs(ImmutableList.of("arg8", "arg9"))
                     .setLaunchImage("test-image")
                     .build())
                 .setCategory("test-category")
@@ -417,12 +421,15 @@ public void testApnsMessageWithPayloadAndAps() throws IOException {
         "aps", ImmutableMap.<String, Object>builder()
             .put("alert", ImmutableMap.<String, Object>builder()
                 .put("title", "test-title")
+                .put("subtitle", "test-subtitle")
                 .put("body", "test-body")
                 .put("loc-key", "test-loc-key")
                 .put("action-loc-key", "test-action-loc-key")
                 .put("title-loc-key", "test-title-loc-key")
+                .put("subtitle-loc-key", "test-subtitle-loc-key")
                 .put("loc-args", ImmutableList.of("arg1", "arg2", "arg3"))
                 .put("title-loc-args", ImmutableList.of("arg4", "arg5", "arg6"))
+                .put("subtitle-loc-args", ImmutableList.of("arg7", "arg8", "arg9"))
                 .put("launch-image", "test-image")
                 .build())
             .put("category", "test-category")
@@ -474,7 +481,8 @@ public void testInvalidApnsConfig() {
 
     List<ApsAlert.Builder> notificationBuilders = ImmutableList.of(
         ApsAlert.builder().addLocalizationArg("foo"),
-        ApsAlert.builder().addTitleLocalizationArg("foo")
+        ApsAlert.builder().addTitleLocalizationArg("foo"),
+        ApsAlert.builder().addSubtitleLocalizationArg("foo")
     );
     for (int i = 0; i < notificationBuilders.size(); i++) {
       try {