diff --git a/android/src/main/java/com/smore/RNSegmentIOAnalytics/RNSegmentIOAnalyticsModule.java b/android/src/main/java/com/smore/RNSegmentIOAnalytics/RNSegmentIOAnalyticsModule.java
index fd39148..378d6c8 100644
--- a/android/src/main/java/com/smore/RNSegmentIOAnalytics/RNSegmentIOAnalyticsModule.java
+++ b/android/src/main/java/com/smore/RNSegmentIOAnalytics/RNSegmentIOAnalyticsModule.java
@@ -86,6 +86,17 @@ public void screen(String screenName, ReadableMap properties) {
     mAnalytics.screen(null, screenName, toProperties(properties));
   }
 
+  /*
+   https://segment.com/docs/libraries/android/#group
+   */
+  @ReactMethod
+  public void group(String groupId, ReadableMap traits) {
+    if (!mEnabled) {
+      return;
+    }
+    mAnalytics.group(groupId, toTraits(traits));
+  }
+
   /*
    https://segment.com/docs/libraries/android/#flushing
    */
@@ -144,13 +155,13 @@ private Properties toProperties (ReadableMap map) {
       ReadableType type = map.getType(key);
       switch (type){
         case Array:
-          props.putValue(key, map.getArray(key));
+          props.putValue(key, map.getArray(key).toArrayList());
           break;
         case Boolean:
           props.putValue(key, map.getBoolean(key));
           break;
         case Map:
-          props.putValue(key, map.getMap(key));
+          props.putValue(key, map.getMap(key).toHashMap());
           break;
         case Null:
           props.putValue(key, null);
@@ -181,13 +192,13 @@ private Traits toTraits (ReadableMap map) {
       ReadableType type = map.getType(key);
       switch (type){
         case Array:
-          traits.putValue(key, map.getArray(key));
+          traits.putValue(key, map.getArray(key).toArrayList());
           break;
         case Boolean:
           traits.putValue(key, map.getBoolean(key));
           break;
         case Map:
-          traits.putValue(key, map.getMap(key));
+          traits.putValue(key, map.getMap(key).toHashMap());
           break;
         case Null:
           traits.putValue(key, null);
diff --git a/index.js b/index.js
index 5ba6e5d..5476820 100644
--- a/index.js
+++ b/index.js
@@ -53,6 +53,14 @@ export default {
         NativeRNSegmentIOAnalytics.screen(screenName, properties || {})
     },
 
+    /*
+     * https://segment.com/docs/libraries/ios/#group
+     * https://segment.com/docs/libraries/android/#group
+     */
+    group: function (groupId: string, traits: ?Object) {
+        NativeRNSegmentIOAnalytics.group(groupId, traits || {})
+    },
+
     /*
      * https://segment.com/docs/libraries/ios/#reset
      * https://segment.com/docs/libraries/android/#how-do-you-handle-unique-identifiers-
diff --git a/ios/RNAnalytics/RNSegmentIOAnalytics.m b/ios/RNAnalytics/RNSegmentIOAnalytics.m
index eb8d668..13e4932 100644
--- a/ios/RNAnalytics/RNSegmentIOAnalytics.m
+++ b/ios/RNAnalytics/RNSegmentIOAnalytics.m
@@ -42,6 +42,13 @@ @implementation RNSegmentIOAnalytics
     [[SEGAnalytics sharedAnalytics] screen:screenName properties:properties];
 }
 
+/*
+ https://segment.com/docs/libraries/ios/#group
+ */
+RCT_EXPORT_METHOD(group:(NSString*)groupId traits:(NSDictionary *)traits) {
+  [[SEGAnalytics sharedAnalytics] group:groupId traits:traits];
+}
+
 /*
  https://segment.com/docs/libraries/ios/#flushing
  */