diff --git a/karma.conf.js b/karma.conf.js
index d0a7683..782da3a 100644
--- a/karma.conf.js
+++ b/karma.conf.js
@@ -55,6 +55,7 @@ module.exports = (config) => {
     reporters: [ 'mocha' ],
 
     files: [
+      'node_modules/es6-shim/es6-shim.js',
       'tests.webpack.js'
     ],
 
diff --git a/modules/Expectation.js b/modules/Expectation.js
index 6db296f..240d395 100644
--- a/modules/Expectation.js
+++ b/modules/Expectation.js
@@ -6,9 +6,11 @@ import {
   isA,
   isFunction,
   isArray,
+  isSet,
   isEqual,
   isObject,
   functionThrows,
+  setContains,
   arrayContains,
   objectContains,
   stringContains
@@ -286,6 +288,8 @@ class Expectation {
 
     if (isArray(this.actual)) {
       contains = arrayContains(this.actual, value, compareValues)
+    } else if (isSet(this.actual)) {
+      contains = setContains(this.actual, value, compareValues)
     } else if (isObject(this.actual)) {
       contains = objectContains(this.actual, value, compareValues)
     } else if (typeof this.actual === 'string') {
@@ -320,6 +324,8 @@ class Expectation {
 
     if (isArray(this.actual)) {
       contains = arrayContains(this.actual, value, compareValues)
+    } else if (isSet(this.actual)) {
+      contains = setContains(this.actual, value, compareValues)
     } else if (isObject(this.actual)) {
       contains = objectContains(this.actual, value, compareValues)
     } else if (typeof this.actual === 'string') {
diff --git a/modules/TestUtils.js b/modules/TestUtils.js
index 7d7ea31..6638d70 100644
--- a/modules/TestUtils.js
+++ b/modules/TestUtils.js
@@ -27,6 +27,29 @@ export const isFunction = (object) =>
 export const isArray = (object) =>
   Array.isArray(object)
 
+
+const hasSet = typeof Set === 'function' && Set.prototype
+const setSizeDescriptor = Object.getOwnPropertyDescriptor && hasSet ?
+  Object.getOwnPropertyDescriptor(Set.prototype, 'size') : null
+const setSize = hasSet && setSizeDescriptor && typeof setSizeDescriptor.get === 'function'
+  ? setSizeDescriptor.get : null
+
+/**
+ * Returns true if the given object is a set.
+ */
+export const isSet = (object) => {
+  if (!setSize) {
+    return false
+  }
+  try {
+    setSize.call(object)
+    return true
+  } catch (err) {
+    return false
+  }
+}
+
+
 /**
  * Returns true if the given object is an object.
  */
@@ -88,6 +111,20 @@ export const functionThrows = (fn, context, args, value) => {
 export const arrayContains = (array, value, compareValues) =>
   array.some(item => compareValues(item, value) !== false)
 
+/**
+ * Returns true if the given array contains the value, false
+ * otherwise. The compareValues function must return false to
+ * indicate a non-match.
+ */
+export const setContains = (set, value, compareValues) => {
+  for (let item of set) {
+    if (compareValues(value, item)) {
+      return true
+    }
+  }
+  return false
+}
+
 const ownEnumerableKeys = (object) => {
   if (typeof Reflect === 'object' && typeof Reflect.ownKeys === 'function') {
     return Reflect.ownKeys(object)
diff --git a/modules/__tests__/toExclude-test.js b/modules/__tests__/toExclude-test.js
index 40a10a2..9b69fd0 100644
--- a/modules/__tests__/toExclude-test.js
+++ b/modules/__tests__/toExclude-test.js
@@ -1,7 +1,7 @@
 import expect from '../index'
 
 describe('toExclude', () => {
-  it('requires the actual value to be an array or string', () => {
+  it('requires the actual value to be an array, object or string', () => {
     expect(() => {
       expect(1).toExclude(2)
     }).toThrow(/must be an array, object, or a string/)
@@ -19,9 +19,21 @@ describe('toExclude', () => {
     }).toThrow(/to exclude/)
   })
 
+  it('does not throw when a set does not contain the expected value', () => {
+    expect(() => {
+      expect(new Set([ 1, 2, 3 ])).toExclude(4)
+    }).toNotThrow()
+  })
+
+  it('throws when a set contains the expected value', () => {
+    expect(() => {
+      expect(new Set([ 1, 2, 3 ])).toExclude(2)
+    }).toThrow(/to exclude/)
+  })
+  
   it('throws when an object contains an expected object', () => {
     expect(() => {
-      expect({ a: 1 }).toExclude({ a: 1 })
+      expect( { a: 1 }).toExclude({ a: 1 })
     }).toThrow(/to exclude/)
   })
 
@@ -31,13 +43,19 @@ describe('toExclude', () => {
     }).toNotThrow()
   })
 
+  it('does not throw when a set contains an unexpected object', () => {
+    expect(() => {
+      expect(new Set([ { a: 1 } ])).toExclude({ b: 2 })
+    }).toNotThrow()
+  })
+
   it('does not throw when an object contains an expected object with an unexpected value', () => {
     expect(() => {
       expect({ a: 1 }).toExclude({ a: 2 })
     }).toNotThrow()
   })
 
-  it('does not throw when an array does not contain the expected value', () => {
+  it('does not throw when a string does not contain the expected value', () => {
     expect(() => {
       expect('hello world').toExclude('goodbye')
     }).toNotThrow()
diff --git a/modules/__tests__/toInclude-test.js b/modules/__tests__/toInclude-test.js
index bfec6eb..dfb789c 100644
--- a/modules/__tests__/toInclude-test.js
+++ b/modules/__tests__/toInclude-test.js
@@ -19,7 +19,19 @@ describe('toInclude', () => {
       expect([ { a: 1 }, { c: 2 } ]).toInclude({ c: 2 })
     }).toNotThrow()
   })
-
+  
+  it('does not throw when a set contains an expected integer', () => {
+    expect(() => {
+      expect(new Set([ 1, 2, 3 ])).toInclude(2)
+    }).toNotThrow()
+  })
+  
+  it('does not throw when a set contains an expected object', () => {
+    expect(() => {
+      expect(new Set([ { a: 1 }, { c: 2} ])).toInclude({ c: 2 })
+    }).toNotThrow()
+  })
+  
   it('does not throw when an object contains an expected object', () => {
     expect(() => {
       expect({ a: 1, b: 2, c: 3 }).toInclude({ b: 2 })
@@ -118,6 +130,18 @@ describe('toInclude', () => {
     }).toThrow(/to include/)
   })
 
+  it('throws when a set does not contain an expected integer', () => {
+    expect(() => {
+      expect(new Set([ 1, 2, 3 ])).toInclude(4)
+    }).toThrow(/to include/)
+  })
+
+  it('throws when a set does not contain an expected object', () => {
+    expect(() => {
+        expect(new Set([ { a: 1 }, { c: 2 } ])).toInclude({ a: 2 })
+    }).toThrow(/to include/)
+  })
+
   it('does not throw when a string contains the expected value', () => {
     expect(() => {
       expect('hello world').toInclude('world')
diff --git a/package.json b/package.json
index a6f66d3..fdd0e03 100644
--- a/package.json
+++ b/package.json
@@ -34,6 +34,7 @@
     "babel-eslint": "^6.1.2",
     "babel-loader": "^6.2.4",
     "babel-preset-es2015": "^6.6.0",
+    "es6-shim": "^0.35.2",
     "eslint": "^3.2.2",
     "eslint-plugin-import": "^1.12.0",
     "gzip-size": "^3.0.0",