diff --git a/src/finalisers/iife.js b/src/finalisers/iife.js
index 6e11ef5..c497c2c 100644
--- a/src/finalisers/iife.js
+++ b/src/finalisers/iife.js
@@ -35,9 +35,10 @@ export default function iife ( bundle, magicString, { exportMode, indentString }
 		args.unshift( 'exports' );
 	}
 
-	const useStrict = options.useStrict !== false ? ` 'use strict';` : ``;
-	let intro = `(function (${args}) {${useStrict}\n\n`;
-	let outro = `\n\n})(${dependencies});`;
+	const useStrict = options.useStrict !== false ? `'use strict';` : ``;
+	if ( useStrict ) magicString.prepend( useStrict + '\n\n' );
+	let intro = `(function (${args}) {\n`;
+	let outro = `\n\n}(${dependencies}));`;
 
 	if ( exportMode === 'default' ) {
 		intro = ( isNamespaced ? `this.` : `var ` ) + `${name} = ${intro}`;
diff --git a/test/form/banner-and-footer-plugin/_expected/iife.js b/test/form/banner-and-footer-plugin/_expected/iife.js
index 03dc18b..36a9599 100644
--- a/test/form/banner-and-footer-plugin/_expected/iife.js
+++ b/test/form/banner-and-footer-plugin/_expected/iife.js
@@ -1,9 +1,10 @@
 /* first banner */
 /* second banner */
-(function () { 'use strict';
+(function () {
+	'use strict';
 
 	console.log( 1 + 1 );
 
-})();
+}());
 /* first footer */
 /* second footer */
diff --git a/test/form/banner-and-footer/_expected/iife.js b/test/form/banner-and-footer/_expected/iife.js
index 8135f24..37662b5 100644
--- a/test/form/banner-and-footer/_expected/iife.js
+++ b/test/form/banner-and-footer/_expected/iife.js
@@ -1,7 +1,8 @@
 /* this is a banner */
-(function () { 'use strict';
+(function () {
+	'use strict';
 
 	console.log( 'hello world' );
 
-})();
+}());
 /* this is a footer */
diff --git a/test/form/block-comments/_expected/iife.js b/test/form/block-comments/_expected/iife.js
index 41a0980..f8fbf52 100644
--- a/test/form/block-comments/_expected/iife.js
+++ b/test/form/block-comments/_expected/iife.js
@@ -1,4 +1,5 @@
-(function () { 'use strict';
+(function () {
+	'use strict';
 
 	function foo () {
 		return embiggen( 6, 7 );
@@ -16,4 +17,4 @@
 
 	alert( foo() );
 
-})();
+}());
diff --git a/test/form/dedupes-external-imports/_expected/iife.js b/test/form/dedupes-external-imports/_expected/iife.js
index 6e465c7..17ed0b7 100644
--- a/test/form/dedupes-external-imports/_expected/iife.js
+++ b/test/form/dedupes-external-imports/_expected/iife.js
@@ -1,4 +1,5 @@
-(function (exports,external) { 'use strict';
+(function (exports,external) {
+	'use strict';
 
 	class Foo extends external.Component {
 		constructor () {
@@ -29,4 +30,4 @@
 	exports.bar = bar;
 	exports.baz = baz;
 
-})((this.myBundle = {}),external);
+}((this.myBundle = {}),external));
diff --git a/test/form/exclude-unnecessary-modifications/_expected/iife.js b/test/form/exclude-unnecessary-modifications/_expected/iife.js
index 0fd4c40..9a3501b 100644
--- a/test/form/exclude-unnecessary-modifications/_expected/iife.js
+++ b/test/form/exclude-unnecessary-modifications/_expected/iife.js
@@ -1,4 +1,5 @@
-(function () { 'use strict';
+(function () {
+	'use strict';
 
 	var foo = {};
 
@@ -25,4 +26,4 @@
 
 	console.log( foo );
 
-})();
+}());