diff --git a/API.md b/API.md
index 62582f782..1fd4e6213 100644
--- a/API.md
+++ b/API.md
@@ -220,7 +220,7 @@ Insert API responses and lifecycle data into Onyx
 
 | Param | Type | Description |
 | --- | --- | --- |
-| data | <code>Array</code> | An array of objects with shape {onyxMethod: oneOf('set', 'merge'), key: string, value: *} |
+| data | <code>Array</code> | An array of objects with shape {onyxMethod: oneOf('set', 'merge', 'mergeCollection'), key: string, value: *} |
 
 <a name="init"></a>
 
diff --git a/lib/Onyx.js b/lib/Onyx.js
index 1ed4db16e..1720367c0 100644
--- a/lib/Onyx.js
+++ b/lib/Onyx.js
@@ -812,12 +812,12 @@ function mergeCollection(collectionKey, collection) {
 /**
  * Insert API responses and lifecycle data into Onyx
  *
- * @param {Array} data An array of objects with shape {onyxMethod: oneOf('set', 'merge'), key: string, value: *}
+ * @param {Array} data An array of objects with shape {onyxMethod: oneOf('set', 'merge', 'mergeCollection'), key: string, value: *}
  */
 function update(data) {
     // First, validate the Onyx object is in the format we expect
     _.each(data, ({onyxMethod, key}) => {
-        if (!_.contains(['set', 'merge'], onyxMethod)) {
+        if (!_.contains(['set', 'merge', 'mergeCollection'], onyxMethod)) {
             throw new Error(`Invalid onyxMethod ${onyxMethod} in Onyx update.`);
         }
         if (!_.isString(key)) {
@@ -833,6 +833,9 @@ function update(data) {
             case 'merge':
                 merge(key, value);
                 break;
+            case 'mergeCollection':
+                mergeCollection(key, value);
+                break;
             default:
                 break;
         }
diff --git a/tests/unit/onyxTest.js b/tests/unit/onyxTest.js
index 670dafe95..48772a81f 100644
--- a/tests/unit/onyxTest.js
+++ b/tests/unit/onyxTest.js
@@ -358,6 +358,89 @@ describe('Onyx', () => {
             });
     });
 
+    it('should use update data object to merge a collection of keys', () => {
+        const valuesReceived = {};
+        const mockCallback = jest.fn(data => valuesReceived[data.ID] = data.value);
+        connectionID = Onyx.connect({
+            key: ONYX_KEYS.COLLECTION.TEST_KEY,
+            initWithStoredValues: false,
+            callback: mockCallback,
+        });
+
+        return waitForPromisesToResolve()
+            .then(() => {
+                // GIVEN the initial Onyx state: {test_1: {existingData: 'test',}, test_2: {existingData: 'test',}}
+                Onyx.multiSet({
+                    test_1: {
+                        existingData: 'test',
+                    },
+                    test_2: {
+                        existingData: 'test',
+                    },
+                });
+                return waitForPromisesToResolve();
+            })
+            .then(() => {
+                expect(mockCallback.mock.calls[0][0]).toEqual({existingData: 'test'});
+                expect(mockCallback.mock.calls[0][1]).toEqual('test_1');
+
+                expect(mockCallback.mock.calls[1][0]).toEqual({existingData: 'test'});
+                expect(mockCallback.mock.calls[1][1]).toEqual('test_2');
+
+                // WHEN we pass a mergeCollection data object to Onyx.update
+                Onyx.update([
+                    {
+                        onyxMethod: 'mergeCollection',
+                        key: ONYX_KEYS.COLLECTION.TEST_KEY,
+                        value: {
+                            test_1: {
+                                ID: 123,
+                                value: 'one',
+                            },
+                            test_2: {
+                                ID: 234,
+                                value: 'two',
+                            },
+                            test_3: {
+                                ID: 345,
+                                value: 'three',
+                            },
+                        },
+                    },
+                ]);
+                return waitForPromisesToResolve();
+            })
+            .then(() => {
+                /* THEN the final Onyx state should be:
+                    {
+                        test_1: {
+                            existingData: 'test'
+                            ID: 123,
+                            value: 'one',
+                        },
+                        test_2: {
+                            existingData: 'test'
+                            ID: 234,
+                            value: 'two',
+                        },
+                        test_3: {
+                            ID: 345,
+                            value: 'three',
+                        },
+                    }
+                */
+
+                expect(mockCallback.mock.calls[2][0]).toEqual({ID: 123, value: 'one', existingData: 'test'});
+                expect(mockCallback.mock.calls[2][1]).toEqual('test_1');
+
+                expect(mockCallback.mock.calls[3][0]).toEqual({ID: 234, value: 'two', existingData: 'test'});
+                expect(mockCallback.mock.calls[3][1]).toEqual('test_2');
+
+                expect(mockCallback.mock.calls[4][0]).toEqual({ID: 345, value: 'three'});
+                expect(mockCallback.mock.calls[4][1]).toEqual('test_3');
+            });
+    });
+
     it('should throw an error when the data object is incorrect in Onyx.update', () => {
         // GIVEN the invalid data object with onyxMethod='multiSet'
         const data = [