diff --git a/packages/polyfill/src/Number.isInteger.js b/packages/polyfill/src/Number.isInteger.js
new file mode 100644
index 0000000..f419285
--- /dev/null
+++ b/packages/polyfill/src/Number.isInteger.js
@@ -0,0 +1,10 @@
+// References:
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isInteger
+
+if (!Number.isInteger)
+{
+    Number.isInteger = function numberIsInteger(value)
+    {
+        return typeof value === 'number' && isFinite(value) && Math.floor(value) === value;
+    };
+}

diff --git a/packages/polyfill/src/Number.isInteger.js b/packages/polyfill/src/Number.isInteger.js
new file mode 100644
index 0000000..f419285
--- /dev/null
+++ b/packages/polyfill/src/Number.isInteger.js
@@ -0,0 +1,10 @@
+// References:
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isInteger
+
+if (!Number.isInteger)
+{
+    Number.isInteger = function numberIsInteger(value)
+    {
+        return typeof value === 'number' && isFinite(value) && Math.floor(value) === value;
+    };
+}
diff --git a/packages/polyfill/src/index.js b/packages/polyfill/src/index.js
index fb2ca08..6ff77c1 100644
--- a/packages/polyfill/src/index.js
+++ b/packages/polyfill/src/index.js
@@ -2,6 +2,7 @@
 import './Object.assign';
 import './requestAnimationFrame';
 import './Math.sign';
+import './Number.isInteger';
 
 if (!window.ArrayBuffer)
 {