diff --git a/src/Form/UserAdminForm.php b/src/Form/UserAdminForm.php
index 3dd30ed3..86ae0f21 100644
--- a/src/Form/UserAdminForm.php
+++ b/src/Form/UserAdminForm.php
@@ -152,6 +152,7 @@ class UserAdminForm extends AbstractType
                 'choice_label' => function ($entity, $key, $value) {
                     return $value;
                 },
+                'attr' => ['class' => 'selectpicker'],
                 'placeholder' => $this->trans->trans('user_settings.theme.placeholder'),
                 'label' => $this->trans->trans('user.theme.label'),
                 'disabled' => !$this->security->isGranted('change_user_settings', $entity)
diff --git a/src/Form/UserSettingsType.php b/src/Form/UserSettingsType.php
index 13177402..1a9ae477 100644
--- a/src/Form/UserSettingsType.php
+++ b/src/Form/UserSettingsType.php
@@ -75,6 +75,7 @@ class UserSettingsType extends AbstractType
                 ])
             ->add('theme', ChoiceType::class, [
                 'required' => false,
+                'attr' => ['class' => 'selectpicker'],
                 'choices' => User::AVAILABLE_THEMES,
                 'choice_label' => function ($entity, $key, $value) {
                     return $value;