diff --git a/includes/Hooks.php b/includes/Hooks.php
index 3a7e950cd..d5badcac7 100644
--- a/includes/Hooks.php
+++ b/includes/Hooks.php
@@ -430,6 +430,30 @@ class Hooks {
 		}
 	}
 
+	/**
+	 * Adds MediaWiki:Vector.css as the skin style that controls classic Vector.
+	 *
+	 * @param string $skin
+	 * @param array &$pages
+	 */
+	public static function onResourceLoaderSiteStylesModulePages( string $skin, array &$pages ) {
+		if ( $skin === Constants::SKIN_NAME_MODERN ) {
+			$pages['MediaWiki:Vector.css'] = [ 'type' => 'style' ];
+		}
+	}
+
+	/**
+	 * Adds MediaWiki:Vector.css as the skin style that controls classic Vector.
+	 *
+	 * @param string $skin
+	 * @param array &$pages
+	 */
+	public static function onResourceLoaderSiteModulePages( string $skin, array &$pages ) {
+		if ( $skin === Constants::SKIN_NAME_MODERN ) {
+			$pages['MediaWiki:Vector.js'] = [ 'type' => 'script' ];
+		}
+	}
+
 	/**
 	 * Hook executed on user's Special:Preferences form save. This is used to convert the boolean
 	 * presentation of skin version to a version string. That is, a single preference change by the
@@ -659,6 +683,25 @@ class Hooks {
 					Constants::CONFIG_KEY_DISABLE_SIDEBAR_PERSISTENCE
 				);
 		}
+
+		// [[phab:T297758]] ensure old Vector is the same as new Vector
+		// from a user script / gadget point of view.
+		if ( self::isSkinVersionLegacy() ) {
+			$vars[ 'skin' ] = 'vector';
+		}
+	}
+
+	/**
+	 * @param array &$vars Array of variables to be added into the output.
+	 * @param string $skin
+	 * @param Config $config
+	 */
+	public static function onResourceLoaderGetConfigVars( array &$vars, string $skin, Config $config ) {
+			// [[phab:T297758]] ensure old Vector is the same as new Vector
+		// from a user script / gadget point of view.
+		if ( self::isVectorSkin( $skin ) ) {
+			$vars['skin'] = 'vector';
+		}
 	}
 
 	/**
diff --git a/includes/ResourceLoader/VectorResourceLoaderUserModule.php b/includes/ResourceLoader/VectorResourceLoaderUserModule.php
new file mode 100644
index 000000000..edcd580e5
--- /dev/null
+++ b/includes/ResourceLoader/VectorResourceLoaderUserModule.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Vector\ResourceLoader;
+
+use ResourceLoaderContext;
+use ResourceLoaderUserModule;
+use Vector\Constants;
+
+class VectorResourceLoaderUserModule extends ResourceLoaderUserModule {
+	/**
+	 * @inheritDoc
+	 */
+	protected function getPages( ResourceLoaderContext $context ) {
+		$skin = $context->getSkin();
+		$config = $this->getConfig();
+		$user = $context->getUserObj();
+		$pages = [];
+		if ( $config->get( 'AllowUserCss' ) && !$user->isAnon() && ( $skin === Constants::SKIN_NAME_MODERN ) ) {
+			$pages = parent::getPages( $context );
+			$userPage = $user->getUserPage()->getPrefixedDBkey();
+			$pages["$userPage/vector.js"] = [ 'type' => 'script' ];
+		}
+		return $pages;
+	}
+}
diff --git a/includes/ResourceLoader/VectorResourceLoaderUserStylesModule.php b/includes/ResourceLoader/VectorResourceLoaderUserStylesModule.php
new file mode 100644
index 000000000..2dfff04b8
--- /dev/null
+++ b/includes/ResourceLoader/VectorResourceLoaderUserStylesModule.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Vector\ResourceLoader;
+
+use ResourceLoaderContext;
+use ResourceLoaderUserStylesModule;
+use Vector\Constants;
+
+class VectorResourceLoaderUserStylesModule extends ResourceLoaderUserStylesModule {
+	/**
+	 * @inheritDoc
+	 */
+	protected function getPages( ResourceLoaderContext $context ) {
+		$skin = $context->getSkin();
+		$config = $this->getConfig();
+		$user = $context->getUserObj();
+		$pages = [];
+		if ( $config->get( 'AllowUserCss' ) && !$user->isAnon() && ( $skin === Constants::SKIN_NAME_MODERN ) ) {
+			$pages = parent::getPages( $context );
+			$userPage = $user->getUserPage()->getPrefixedDBkey();
+			$pages["$userPage/vector.css"] = [ 'type' => 'style' ];
+		}
+		return $pages;
+	}
+}
diff --git a/includes/SkinVector22.php b/includes/SkinVector22.php
index b596f3a3d..30397cd59 100644
--- a/includes/SkinVector22.php
+++ b/includes/SkinVector22.php
@@ -33,6 +33,7 @@ class SkinVector22 extends SkinVector {
 	 */
 	public static function getScriptsOption() {
 		return [
+			'skins.vector.user',
 			'skins.vector.js',
 			'skins.vector.es6',
 		];
@@ -47,6 +48,7 @@ class SkinVector22 extends SkinVector {
 		return [
 			'mediawiki.ui.button',
 			'skins.vector.styles',
+			'skins.vector.user.styles',
 			'skins.vector.icons',
 			'mediawiki.ui.icon',
 		];
diff --git a/skin.json b/skin.json
index 38ad9a7ac..120d6f170 100644
--- a/skin.json
+++ b/skin.json
@@ -115,6 +115,9 @@
 		"vector": "GlobalVarConfig::newInstance"
 	},
 	"Hooks": {
+		"ResourceLoaderGetConfigVars": "Vector\\Hooks::onResourceLoaderGetConfigVars",
+		"ResourceLoaderSiteModulePages": "Vector\\Hooks::onResourceLoaderSiteModulePages",
+		"ResourceLoaderSiteStylesModulePages": "Vector\\Hooks::onResourceLoaderSiteStylesModulePages",
 		"SkinPageReadyConfig": "Vector\\Hooks::onSkinPageReadyConfig",
 		"GetPreferences": "Vector\\Hooks::onGetPreferences",
 		"PreferencesFormPreSave": "Vector\\Hooks::onPreferencesFormPreSave",
@@ -124,6 +127,12 @@
 	},
 	"@note": "When modifying skins.vector.styles definition, make sure the installer still works",
 	"ResourceModules": {
+		"skins.vector.user": {
+			"class": "Vector\\ResourceLoader\\VectorResourceLoaderUserModule"
+		},
+		"skins.vector.user.styles": {
+			"class": "Vector\\ResourceLoader\\VectorResourceLoaderUserStylesModule"
+		},
 		"skins.vector.search": {
 			"dependencies": [
 				"mediawiki.Uri",