diff --git a/manifest.php b/manifest.php
index 021c27e9..cb1145e9 100755
--- a/manifest.php
+++ b/manifest.php
@@ -30,6 +30,7 @@
 use oat\taoLti\scripts\install\CreateLti1p3RegistrationSnapshotSchema;
 use oat\taoLti\scripts\install\GenerateKeys;
 use oat\taoLti\scripts\install\GenerisSearchWhitelist;
+use oat\taoLti\scripts\install\RegisterPortalTheme;
 use oat\taoLti\scripts\install\SetupServices;
 use oat\taoLti\scripts\install\MapLtiSectionVisibility;
 use oat\taoLti\scripts\update\Updater;
@@ -66,6 +67,7 @@
             MapLtiSectionVisibility::class,
             GenerisSearchWhitelist::class,
             CreateLti1p3RegistrationSnapshotSchema::class,
+            RegisterPortalTheme::class
         ]
     ],
     'update' => Updater::class,
diff --git a/migrations/Version202406060802293772_taoLti.php b/migrations/Version202406060802293772_taoLti.php
new file mode 100644
index 00000000..8666a5dc
--- /dev/null
+++ b/migrations/Version202406060802293772_taoLti.php
@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace oat\taoLti\migrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use oat\tao\scripts\tools\migrations\AbstractMigration;
+use oat\taoLti\scripts\install\RegisterPortalTheme;
+use oat\taoQtiTest\scripts\install\RegisterQtiPackageExporter;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ *
+ * phpcs:disable Squiz.Classes.ValidClassName
+ */
+final class Version202406060802293772_taoLti extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return '';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->runAction(new RegisterPortalTheme());
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->throwIrreversibleMigrationException();
+    }
+}
diff --git a/models/classes/theme/PortalThemeService.php b/models/classes/theme/PortalThemeService.php
new file mode 100644
index 00000000..2381084e
--- /dev/null
+++ b/models/classes/theme/PortalThemeService.php
@@ -0,0 +1,48 @@
+<?php
+
+/**
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; under version 2
+ * of the License (non-upgradable).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (c) 2024 (original work) Open Assessment Technologies SA;
+ */
+
+declare(strict_types=1);
+
+namespace oat\taoLti\models\classes\theme;
+
+use common_session_SessionManager;
+use oat\tao\model\session\Context\TenantDataSessionContext;
+use oat\tao\model\theme\PortalTheme;
+use oat\tao\model\theme\ThemeService;
+use oat\taoLti\models\classes\TaoLtiSession;
+
+class PortalThemeService extends ThemeService
+{
+    public function getCurrentThemeId()
+    {
+        if ($this->isSessionFromPortal()) {
+            return PortalTheme::THEME_ID;
+        }
+
+        return $this->getOption(static::OPTION_CURRENT);
+    }
+
+    private function isSessionFromPortal(): bool
+    {
+        $session = common_session_SessionManager::getSession();
+        return $session instanceof TaoLtiSession
+            && !empty($session->getContexts(TenantDataSessionContext::class));
+    }
+}
diff --git a/scripts/install/RegisterPortalTheme.php b/scripts/install/RegisterPortalTheme.php
new file mode 100644
index 00000000..12760d7e
--- /dev/null
+++ b/scripts/install/RegisterPortalTheme.php
@@ -0,0 +1,45 @@
+<?php
+
+/**
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; under version 2
+ * of the License (non-upgradable).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (c) 2024 (original work) Open Assessment Technologies SA;
+ */
+
+declare(strict_types=1);
+
+namespace oat\taoLti\scripts\install;
+
+use oat\oatbox\config\ConfigurationService;
+use oat\oatbox\extension\InstallAction;
+use oat\tao\model\theme\PortalTheme;
+use oat\tao\model\theme\ThemeServiceInterface;
+use oat\taoLti\models\classes\theme\PortalThemeService;
+
+class RegisterPortalTheme extends InstallAction
+{
+    public function __invoke($params = [])
+    {
+        /** @var ConfigurationService $previousThemeService */
+        $previousThemeService = $this->getServiceManager()->get(ThemeServiceInterface::SERVICE_ID);
+
+        /** @var ThemeServiceInterface $service */
+        $service = $this->propagate(new PortalThemeService());
+        $service->setOptions($previousThemeService->getOptions());
+        $service->addTheme(new PortalTheme(), false);
+
+        $this->getServiceManager()->register(ThemeServiceInterface::SERVICE_ID, $service);
+    }
+}