diff --git a/package-lock.json b/package-lock.json
index f2adec4747775..d271460d9649f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -26618,6 +26618,11 @@
 			"resolved": "https://registry.npmjs.org/which-module/-/which-module-2.0.0.tgz",
 			"integrity": "sha512-B+enWhmw6cjfVC7kS8Pj9pCrKSc5txArRyaYGe088shv/FGWH+0Rjx/xPgtsWfsUtS27FkP697E4DDhgrgoc0Q=="
 		},
+		"wicg-inert": {
+			"version": "3.1.2",
+			"resolved": "https://registry.npmjs.org/wicg-inert/-/wicg-inert-3.1.2.tgz",
+			"integrity": "sha512-Ba9tGNYxXwaqKEi9sJJvPMKuo063umUPsHN0JJsjrs2j8KDSzkWLMZGZ+MH1Jf1Fq4OWZ5HsESJID6nRza2ang=="
+		},
 		"wildcard": {
 			"version": "2.0.0",
 			"resolved": "https://registry.npmjs.org/wildcard/-/wildcard-2.0.0.tgz",
diff --git a/package.json b/package.json
index 73258d249cf11..c459eca491322 100644
--- a/package.json
+++ b/package.json
@@ -154,7 +154,8 @@
 		"regenerator-runtime": "0.13.9",
 		"twemoji": "14.0.2",
 		"underscore": "1.13.6",
-		"whatwg-fetch": "3.6.2"
+		"whatwg-fetch": "3.6.2",
+		"wicg-inert": "3.1.2"
 	},
 	"scripts": {
 		"build": "grunt build",
diff --git a/src/wp-includes/script-loader.php b/src/wp-includes/script-loader.php
index 093d52b284fc3..1444727f9dae7 100644
--- a/src/wp-includes/script-loader.php
+++ b/src/wp-includes/script-loader.php
@@ -99,7 +99,8 @@ function wp_default_packages_vendor( $scripts ) {
 		'wp-polyfill-dom-rect',
 		'wp-polyfill-element-closest',
 		'wp-polyfill-object-fit',
-		'wp-polyfill' => array( 'regenerator-runtime' ),
+		'wp-polyfill-inert',
+		'wp-polyfill' => array( 'wp-polyfill-inert', 'regenerator-runtime' ),
 	);
 
 	$vendor_scripts_versions = array(
@@ -115,6 +116,7 @@ function wp_default_packages_vendor( $scripts ) {
 		'wp-polyfill-dom-rect'        => '4.4.0',
 		'wp-polyfill-element-closest' => '2.0.2',
 		'wp-polyfill-object-fit'      => '2.3.5',
+		'wp-polyfill-inert'           => '3.1.2',
 		'wp-polyfill'                 => '3.15.0',
 	);
 
diff --git a/tests/phpunit/tests/dependencies/scripts.php b/tests/phpunit/tests/dependencies/scripts.php
index 3897c6aa25f94..10e447728a53b 100644
--- a/tests/phpunit/tests/dependencies/scripts.php
+++ b/tests/phpunit/tests/dependencies/scripts.php
@@ -723,7 +723,7 @@ public function test_wp_add_inline_script_before_after_concat_with_core_dependen
 
 		$ver       = get_bloginfo( 'version' );
 		$suffix    = wp_scripts_get_suffix();
-		$expected  = "<script type='text/javascript' src='/wp-admin/load-scripts.php?c=0&amp;load%5Bchunk_0%5D=jquery-core,jquery-migrate,regenerator-runtime,wp-polyfill,wp-dom-ready,wp-hooks&amp;ver={$ver}'></script>\n";
+		$expected  = "<script type='text/javascript' src='/wp-admin/load-scripts.php?c=0&amp;load%5Bchunk_0%5D=jquery-core,jquery-migrate,wp-polyfill-inert,regenerator-runtime,wp-polyfill,wp-dom-ready,wp-hooks&amp;ver={$ver}'></script>\n";
 		$expected .= "<script type='text/javascript' id='test-example-js-before'>\nconsole.log(\"before\");\n</script>\n";
 		$expected .= "<script type='text/javascript' src='http://example.com' id='test-example-js'></script>\n";
 		$expected .= "<script type='text/javascript' src='/wp-includes/js/dist/i18n.min.js' id='wp-i18n-js'></script>\n";
diff --git a/tools/webpack/packages.js b/tools/webpack/packages.js
index bc2daa640a682..671fb4a099fec 100644
--- a/tools/webpack/packages.js
+++ b/tools/webpack/packages.js
@@ -71,6 +71,7 @@ module.exports = function( env = { environment: 'production', watch: false, buil
 		'wp-polyfill-dom-rect.js': 'polyfill-library/polyfills/__dist/DOMRect/raw.js',
 		'wp-polyfill-formdata.js': 'formdata-polyfill/FormData.js',
 		'wp-polyfill-object-fit.js': 'objectFitPolyfill/src/objectFitPolyfill.js',
+		'wp-polyfill-inert.js': 'wicg-inert/dist/inert.js',
 		'moment.js': 'moment/moment.js',
 		'react.js': 'react/umd/react.development.js',
 		'react-dom.js': 'react-dom/umd/react-dom.development.js',
@@ -83,6 +84,7 @@ module.exports = function( env = { environment: 'production', watch: false, buil
 		'wp-polyfill-formdata.min.js': 'formdata-polyfill/formdata.min.js',
 		'wp-polyfill-url.min.js': 'core-js-url-browser/url.min.js',
 		'wp-polyfill-object-fit.min.js': 'objectFitPolyfill/dist/objectFitPolyfill.min.js',
+		'wp-polyfill-inert.min.js': 'wicg-inert/dist/inert.min.js',
 		'moment.min.js': 'moment/min/moment.min.js',
 		'react.min.js': 'react/umd/react.production.min.js',
 		'react-dom.min.js': 'react-dom/umd/react-dom.production.min.js',