diff --git a/Gruntfile.js b/Gruntfile.js
index 5f9109fac3cb0..540eb06aabc94 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -453,6 +453,7 @@ module.exports = function(grunt) {
 					[ WORKING_DIR + 'wp-admin/js/theme-plugin-editor.js' ]: [ './src/js/_enqueues/wp/theme-plugin-editor.js' ],
 					[ WORKING_DIR + 'wp-admin/js/theme.js' ]: [ './src/js/_enqueues/wp/theme.js' ],
 					[ WORKING_DIR + 'wp-admin/js/updates.js' ]: [ './src/js/_enqueues/wp/updates.js' ],
+					[ WORKING_DIR + 'wp-admin/js/wp-options-unsaved-changes-confirmation.js' ]: [ './src/js/_enqueues/admin/wp-options-unsaved-changes-confirmation.js' ],
 					[ WORKING_DIR + 'wp-admin/js/user-profile.js' ]: [ './src/js/_enqueues/admin/user-profile.js' ],
 					[ WORKING_DIR + 'wp-admin/js/user-suggest.js' ]: [ './src/js/_enqueues/lib/user-suggest.js' ],
 					[ WORKING_DIR + 'wp-admin/js/widgets/custom-html-widgets.js' ]: [ './src/js/_enqueues/wp/widgets/custom-html.js' ],
@@ -1192,6 +1193,7 @@ module.exports = function(grunt) {
 					'src/wp-admin/js/theme-plugin-editor.js': 'src/js/_enqueues/wp/theme-plugin-editor.js',
 					'src/wp-admin/js/theme.js': 'src/js/_enqueues/wp/theme.js',
 					'src/wp-admin/js/updates.js': 'src/js/_enqueues/wp/updates.js',
+					'src/wp-admin/js/wp-options-unsaved-changes-confirmation.js': 'src/js/_enqueues/admin/wp-options-unsaved-changes-confirmation.js',
 					'src/wp-admin/js/user-profile.js': 'src/js/_enqueues/admin/user-profile.js',
 					'src/wp-admin/js/user-suggest.js': 'src/js/_enqueues/lib/user-suggest.js',
 					'src/wp-admin/js/widgets/custom-html-widgets.js': 'src/js/_enqueues/wp/widgets/custom-html.js',
diff --git a/src/js/_enqueues/admin/wp-options-unsaved-changes-confirmation.js b/src/js/_enqueues/admin/wp-options-unsaved-changes-confirmation.js
new file mode 100644
index 0000000000000..8dd4017889253
--- /dev/null
+++ b/src/js/_enqueues/admin/wp-options-unsaved-changes-confirmation.js
@@ -0,0 +1,31 @@
+/* global wp */
+( function () {
+	var form = document.querySelector( 'form[action="options.php"]' );
+
+	if ( ! form ) {
+		return;
+	}
+
+	var originalFormContent = new URLSearchParams( new FormData( form ) ).toString();
+	var __ = wp.i18n.__;
+
+	function beforeUnloadHandler( event ) {
+		var currentContent = new URLSearchParams( new FormData( form ) ).toString();
+		if ( originalFormContent !== currentContent ) {
+			event.preventDefault();
+			return __(
+				'The changes you made will be lost if you navigate away from this page.'
+			);
+		}
+	}
+
+	// Add the beforeunload listener only once a field is modified, to avoid
+	// breaking bfcache.
+	document.addEventListener( 'change', function () {
+		window.addEventListener( 'beforeunload', beforeUnloadHandler );
+	}, { once: true } );
+
+	form.addEventListener( 'submit', function () {
+		window.removeEventListener( 'beforeunload', beforeUnloadHandler );
+	} );
+} )();
diff --git a/src/wp-admin/options-discussion.php b/src/wp-admin/options-discussion.php
index 0c350475fe176..2f9fa4226c1a4 100644
--- a/src/wp-admin/options-discussion.php
+++ b/src/wp-admin/options-discussion.php
@@ -33,6 +33,8 @@
 	'<p>' . __( '<a href="https://wordpress.org/support/forums/">Support forums</a>' ) . '</p>'
 );
 
+wp_enqueue_script( 'wp-admin-unsaved-changes-confirmation' );
+
 require_once ABSPATH . 'wp-admin/admin-header.php';
 ?>
 
diff --git a/src/wp-admin/options-general.php b/src/wp-admin/options-general.php
index 969065b7008f4..4c167f27b89d2 100644
--- a/src/wp-admin/options-general.php
+++ b/src/wp-admin/options-general.php
@@ -61,6 +61,8 @@
 	'<p>' . __( '<a href="https://wordpress.org/support/forums/">Support forums</a>' ) . '</p>'
 );
 
+wp_enqueue_script( 'wp-admin-unsaved-changes-confirmation' );
+
 require_once ABSPATH . 'wp-admin/admin-header.php';
 ?>
 
diff --git a/src/wp-admin/options-media.php b/src/wp-admin/options-media.php
index 81ebc9223f543..4172c77eb289d 100644
--- a/src/wp-admin/options-media.php
+++ b/src/wp-admin/options-media.php
@@ -42,6 +42,8 @@
 	'<p>' . __( '<a href="https://wordpress.org/support/forums/">Support forums</a>' ) . '</p>'
 );
 
+wp_enqueue_script( 'wp-admin-unsaved-changes-confirmation' );
+
 require_once ABSPATH . 'wp-admin/admin-header.php';
 
 ?>
diff --git a/src/wp-admin/options-permalink.php b/src/wp-admin/options-permalink.php
index 046c237b6a948..2e551276a12a5 100644
--- a/src/wp-admin/options-permalink.php
+++ b/src/wp-admin/options-permalink.php
@@ -69,6 +69,8 @@
 get_current_screen()->set_help_sidebar( $help_sidebar_content );
 unset( $help_sidebar_content );
 
+wp_enqueue_script( 'wp-admin-unsaved-changes-confirmation' );
+
 $home_path           = get_home_path();
 $iis7_permalinks     = iis7_supports_permalinks();
 $permalink_structure = get_option( 'permalink_structure' );
diff --git a/src/wp-admin/options-reading.php b/src/wp-admin/options-reading.php
index 31facac7edcca..95f61733d7ec7 100644
--- a/src/wp-admin/options-reading.php
+++ b/src/wp-admin/options-reading.php
@@ -54,6 +54,8 @@
 	'<p>' . __( '<a href="https://wordpress.org/support/forums/">Support forums</a>' ) . '</p>'
 );
 
+wp_enqueue_script( 'wp-admin-unsaved-changes-confirmation' );
+
 require_once ABSPATH . 'wp-admin/admin-header.php';
 ?>
 
diff --git a/src/wp-admin/options-writing.php b/src/wp-admin/options-writing.php
index d40dc0578b315..ac3441c664f6c 100644
--- a/src/wp-admin/options-writing.php
+++ b/src/wp-admin/options-writing.php
@@ -55,6 +55,7 @@
 );
 
 wp_enqueue_script( 'user-profile' );
+wp_enqueue_script( 'wp-admin-unsaved-changes-confirmation' );
 
 require_once ABSPATH . 'wp-admin/admin-header.php';
 ?>
diff --git a/src/wp-includes/script-loader.php b/src/wp-includes/script-loader.php
index 42d42b3f8781d..e8b09a98ad92b 100644
--- a/src/wp-includes/script-loader.php
+++ b/src/wp-includes/script-loader.php
@@ -1260,6 +1260,9 @@ function wp_default_scripts( $scripts ) {
 
 	$scripts->add( 'language-chooser', "/wp-admin/js/language-chooser$suffix.js", array( 'jquery' ), false, 1 );
 
+	$scripts->add( 'wp-admin-unsaved-changes-confirmation', "/wp-admin/js/wp-options-unsaved-changes-confirmation$suffix.js", array( 'wp-i18n' ), false, 1 );
+	$scripts->set_translations( 'wp-admin-unsaved-changes-confirmation' );
+
 	$scripts->add( 'user-suggest', "/wp-admin/js/user-suggest$suffix.js", array( 'jquery-ui-autocomplete' ), false, 1 );
 
 	$scripts->add( 'admin-bar', "/wp-includes/js/admin-bar$suffix.js", array( 'hoverintent-js' ), false, 1 );