diff --git a/lib/sinon/assert.js b/lib/sinon/assert.js
index f7e0e35c1..372646f6a 100644
--- a/lib/sinon/assert.js
+++ b/lib/sinon/assert.js
@@ -157,7 +157,7 @@ assert = {
 
         var o = options || {};
         var prefix = typeof o.prefix === "undefined" && "assert" || o.prefix;
-        var includeFail = typeof o.includeFail === "undefined" || !!o.includeFail;
+        var includeFail = typeof o.includeFail === "undefined" || Boolean(o.includeFail);
         var instance = this;
 
         forEach(Object.keys(instance), function (method) {
diff --git a/lib/sinon/blob.js b/lib/sinon/blob.js
index 78a5dd8ba..8f386d231 100644
--- a/lib/sinon/blob.js
+++ b/lib/sinon/blob.js
@@ -3,7 +3,7 @@
 
 exports.isSupported = (function () {
     try {
-        return !!new Blob();
+        return Boolean(new Blob());
     } catch (e) {
         return false;
     }
diff --git a/lib/sinon/call.js b/lib/sinon/call.js
index 4fdce5b0a..97435612c 100644
--- a/lib/sinon/call.js
+++ b/lib/sinon/call.js
@@ -77,7 +77,7 @@ var callProto = {
 
     threw: function threw(error) {
         if (typeof error === "undefined" || !this.exception) {
-            return !!this.exception;
+            return Boolean(this.exception);
         }
 
         return this.exception === error || this.exception.name === error;
diff --git a/lib/sinon/match.js b/lib/sinon/match.js
index a7044d1d5..81434f031 100644
--- a/lib/sinon/match.js
+++ b/lib/sinon/match.js
@@ -177,7 +177,7 @@ match.defined = match(function (actual) {
 }, "defined");
 
 match.truthy = match(function (actual) {
-    return !!actual;
+    return Boolean(actual);
 }, "truthy");
 
 match.falsy = match(function (actual) {
@@ -279,7 +279,7 @@ match.every = function (predicate) {
             });
         }
 
-        return !!actual && typeOf(actual.forEach) === "function" && every(actual, function (element) {
+        return Boolean(actual) && typeOf(actual.forEach) === "function" && every(actual, function (element) {
             return predicate.test(element);
         });
     }, "every(" + predicate.message + ")");
@@ -297,7 +297,7 @@ match.some = function (predicate) {
             });
         }
 
-        return !!actual && typeOf(actual.forEach) === "function" && !every(actual, function (element) {
+        return Boolean(actual) && typeOf(actual.forEach) === "function" && !every(actual, function (element) {
             return !predicate.test(element);
         });
     }, "some(" + predicate.message + ")");
diff --git a/lib/sinon/util/core/wrap-method.js b/lib/sinon/util/core/wrap-method.js
index 811b95444..55ea77001 100644
--- a/lib/sinon/util/core/wrap-method.js
+++ b/lib/sinon/util/core/wrap-method.js
@@ -5,7 +5,7 @@ var hasOwnProperty = require("@sinonjs/commons").prototypes.object.hasOwnPropert
 var valueToString = require("@sinonjs/commons").valueToString;
 
 function isFunction(obj) {
-    return typeof obj === "function" || !!(obj && obj.constructor && obj.call && obj.apply);
+    return typeof obj === "function" || Boolean(obj && obj.constructor && obj.call && obj.apply);
 }
 
 function mirrorProperties(target, source) {
diff --git a/test/sandbox-test.js b/test/sandbox-test.js
index 3ba146880..05b33c819 100644
--- a/test/sandbox-test.js
+++ b/test/sandbox-test.js
@@ -19,7 +19,7 @@ var sinonAssert = require("../lib/sinon/assert");
 var sinonClock = require("../lib/sinon/util/fake_timers");
 
 var supportsAjax = typeof XMLHttpRequest !== "undefined" || typeof ActiveXObject !== "undefined";
-var supportPromise = !!global.Promise;
+var supportPromise = Boolean(global.Promise);
 var globalXHR = global.XMLHttpRequest;
 var globalAXO = global.ActiveXObject;
 
diff --git a/test/util/fake-timers-test.js b/test/util/fake-timers-test.js
index 7df6685e5..b52f1c8c4 100644
--- a/test/util/fake-timers-test.js
+++ b/test/util/fake-timers-test.js
@@ -1016,8 +1016,8 @@ describe("fakeTimers.clock", function () {
         it("fake Date constructor should mirror Date's properties", function () {
             this.clock = fakeTimers.useFakeTimers(0);
 
-            assert(!!Date.parse);
-            assert(!!Date.UTC);
+            assert(Boolean(Date.parse));
+            assert(Boolean(Date.UTC));
         });
 
         it("decide on Date.now support at call-time when supported", function () {