diff --git a/lodash/lodash-tests.ts b/lodash/lodash-tests.ts
index ca0404c11..3e3e7e101 100644
--- a/lodash/lodash-tests.ts
+++ b/lodash/lodash-tests.ts
@@ -758,9 +758,34 @@ module TestTakeWhile {
     result = _(list).takeWhile<{a: number;}, TResult>({a: 42}).value();
 }
 
-result = <number[]>_.union([1, 2, 3], [101, 2, 1, 10], [2, 1]);
+// _.union
+module TestUnion {
+    let array: TResult[];
+    let list: _.List<TResult>;
+    let result: TResult[];
 
-result = <number[]>_([1, 2, 3]).union([101, 2, 1, 10], [2, 1]).value();
+    result = _.union<TResult>();
+
+    result = _.union<TResult>(array);
+    result = _.union<TResult>(array, list);
+    result = _.union<TResult>(array, list, array);
+
+    result = _.union<TResult>(list);
+    result = _.union<TResult>(list, array);
+    result = _.union<TResult>(list, array, list);
+
+    result = _(array).union().value();
+    result = _(array).union(list).value();
+    result = _(array).union(list, array).value();
+
+    result = _(array).union<TResult>().value();
+    result = _(array).union<TResult>(list).value();
+    result = _(array).union<TResult>(list, array).value();
+
+    result = _(list).union<TResult>().value();
+    result = _(list).union<TResult>(array).value();
+    result = _(list).union<TResult>(array, list).value();
+}
 
 result = <number[]>_.uniq([1, 2, 1, 3, 1]);
 result = <number[]>_.uniq([1, 1, 2, 2, 3], true);
diff --git a/lodash/lodash.d.ts b/lodash/lodash.d.ts
index 685e43a96..423c232fa 100644
--- a/lodash/lodash.d.ts
+++ b/lodash/lodash.d.ts
@@ -1651,24 +1651,32 @@ declare module _ {
     //_.union
     interface LoDashStatic {
         /**
-        * Creates an array of unique values, in order, of the provided arrays using strict
-        * equality for comparisons, i.e. ===.
-        * @param arrays The arrays to inspect.
-        * @return Returns an array of composite values.
-        **/
-        union<T>(...arrays: Array<T>[]): T[];
-
-        /**
-        * @see _.union
-        **/
+         * Creates an array of unique values, in order, from all of the provided arrays using SameValueZero for
+         * equality comparisons.
+         *
+         * @param arrays The arrays to inspect.
+         * @return Returns the new array of combined values.
+         */
         union<T>(...arrays: List<T>[]): T[];
     }
 
     interface LoDashArrayWrapper<T> {
         /**
-        * @see _.union
-        **/
-        union<T>(...arrays: (Array<T>|List<T>)[]): LoDashArrayWrapper<T>;
+         * @see _.union
+         */
+        union(...arrays: List<T>[]): LoDashArrayWrapper<T>;
+
+        /**
+         * @see _.union
+         */
+        union<T>(...arrays: List<T>[]): LoDashArrayWrapper<T>;
+    }
+
+    interface LoDashObjectWrapper<T> {
+        /**
+         * @see _.union
+         */
+        union<T>(...arrays: List<T>[]): LoDashArrayWrapper<T>;
     }
 
     //_.uniq