diff --git a/config/packages/security.yaml b/config/packages/security.yaml
index d0c65fb..7400747 100644
--- a/config/packages/security.yaml
+++ b/config/packages/security.yaml
@@ -21,6 +21,7 @@ security:
             provider: bpn_user_provider
             custom_authenticators:
                 - App\Security\BpnAuthenticator
+            user_checker: App\Security\UserChecker
             switch_user:
                 role: CAN_IMPERSONATE
             logout:
diff --git a/migrations/Version20250722142834.php b/migrations/Version20250722142834.php
new file mode 100644
index 0000000..0b7cfe6
--- /dev/null
+++ b/migrations/Version20250722142834.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20250722142834 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return '';
+    }
+
+    public function up(Schema $schema): void
+    {
+        // this up() migration is auto-generated, please modify it to your needs
+        $this->addSql('ALTER TABLE user ADD disabled_at DATETIME DEFAULT NULL COMMENT \'(DC2Type:datetime_immutable)\', ADD disabled_reason LONGTEXT DEFAULT NULL, ADD disabled_reason_internal LONGTEXT DEFAULT NULL');
+    }
+
+    public function down(Schema $schema): void
+    {
+        // this down() migration is auto-generated, please modify it to your needs
+        $this->addSql('ALTER TABLE user DROP disabled_at, DROP disabled_reason, DROP disabled_reason_internal');
+    }
+}
diff --git a/src/Controller/Admin/Teamer/DisableUserController.php b/src/Controller/Admin/Teamer/DisableUserController.php
new file mode 100644
index 0000000..aa9d331
--- /dev/null
+++ b/src/Controller/Admin/Teamer/DisableUserController.php
@@ -0,0 +1,81 @@
+<?php
+
+namespace App\Controller\Admin\Teamer;
+
+use App\Entity\Teamer;
+use App\Form\DisableUserType;
+use App\Htmx\HxRedirectResponse;
+use Doctrine\ORM\EntityManagerInterface;
+use Psr\Log\LoggerInterface;
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\Routing\Attribute\Route;
+use Symfony\Component\Security\Http\Attribute\IsGranted;
+
+class DisableUserController extends AbstractController
+{
+    public function __construct(
+        private readonly EntityManagerInterface $entityManager,
+        private readonly LoggerInterface $logger,
+    ) {
+    }
+
+    #[Route('/admin/teamer/disable-user/{uuid}', name: 'app_admin_teamer_disable_user')]
+    #[IsGranted('ROLE_ADMIN')]
+    public function index(Teamer $teamer, Request $request): Response
+    {
+        $user = $teamer->getUser();
+        $form = $this->createForm(DisableUserType::class, $user, ['hx_post' => $request->getUri()]);
+        $form->handleRequest($request);
+        if ($form->isSubmitted() && $form->isValid()) {
+            $user->setDisabledAt(new \DateTimeImmutable());
+
+            $this->entityManager->flush();
+
+            $this->addFlash('success', 'Der Benutzeraccount wurde gesperrt');
+
+            $this->logger->info('Disable user', [
+                'teamer' => $teamer->getFullName(),
+                'user' => $user->getEmail(),
+            ]);
+
+            return new HxRedirectResponse($this->generateUrl('app_administrative_teamer_index'));
+        }
+
+        return $this->render('admin/teamer/modal_disable_user.html.twig', [
+            'form' => $form->createView(),
+            'teamer' => $teamer,
+        ]);
+    }
+
+    #[Route('/administrative/teamer/enable-user/{uuid}', name: 'app_admin_teamer_enable_user')]
+    #[IsGranted('ROLE_ADMIN')]
+    public function enable(Teamer $teamer, Request $request): Response
+    {
+        $user = $teamer->getUser();
+
+        if (true === $request->isMethod(Request::METHOD_POST)) {
+            $user
+                ->setDisabledAt(null)
+                ->setDisabledReason(null)
+                ->setDisabledReasonInternal(null)
+            ;
+
+            $this->entityManager->flush();
+
+            $this->addFlash('success', 'Der Benutzeraccount wurde reaktiviert');
+
+            $this->logger->info('Enable user', [
+                'teamer' => $teamer->getFullName(),
+                'user' => $user->getEmail(),
+            ]);
+
+            return new HxRedirectResponse($this->generateUrl('app_administrative_teamer_index'));
+        }
+
+        return $this->render('admin/teamer/modal_enable_user.html.twig', [
+            'teamer' => $teamer,
+        ]);
+    }
+}
diff --git a/src/Entity/User.php b/src/Entity/User.php
index dce5872..385eff1 100644
--- a/src/Entity/User.php
+++ b/src/Entity/User.php
@@ -4,6 +4,7 @@ namespace App\Entity;
 
 use App\Entity\Traits\TimestampableEntity;
 use App\Repository\UserRepository;
+use Doctrine\DBAL\Types\Types;
 use Doctrine\ORM\Mapping as ORM;
 use Symfony\Component\Security\Core\User\UserInterface;
 use Symfony\Component\Uid\Uuid;
@@ -57,6 +58,15 @@ class User implements UserInterface, TimestampableEntityInterface
     #[ORM\Column]
     private bool $muteNotifications = false;
 
+    #[ORM\Column(type: 'datetime_immutable', nullable: true)]
+    private ?\DateTimeImmutable $disabledAt = null;
+
+    #[ORM\Column(type: Types::TEXT, nullable: true)]
+    private ?string $disabledReason = null;
+
+    #[ORM\Column(type: Types::TEXT, nullable: true)]
+    private ?string $disabledReasonInternal = null;
+
     public function __construct()
     {
         $this->uuid = Uuid::v4();
@@ -169,7 +179,7 @@ class User implements UserInterface, TimestampableEntityInterface
         $labels = [];
 
         foreach ($this->roles as $role) {
-            $labels[] = match($role) {
+            $labels[] = match ($role) {
                 'ROLE_ADMIN' => 'Admin',
                 'ROLE_MANAGER' => 'Reisemanager',
                 'ROLE_HOUSE_MANAGER' => 'Hausleitung',
@@ -300,4 +310,45 @@ class User implements UserInterface, TimestampableEntityInterface
 
         return false;
     }
+
+    public function getDisabledAt(): ?\DateTimeImmutable
+    {
+        return $this->disabledAt;
+    }
+
+    public function setDisabledAt(?\DateTimeImmutable $disabledAt): static
+    {
+        $this->disabledAt = $disabledAt;
+
+        return $this;
+    }
+
+    public function isDisabled(): bool
+    {
+        return null !== $this->disabledAt;
+    }
+
+    public function getDisabledReason(): ?string
+    {
+        return $this->disabledReason;
+    }
+
+    public function setDisabledReason(?string $disabledReason): static
+    {
+        $this->disabledReason = $disabledReason;
+
+        return $this;
+    }
+
+    public function getDisabledReasonInternal(): ?string
+    {
+        return $this->disabledReasonInternal;
+    }
+
+    public function setDisabledReasonInternal(?string $disabledReasonInternal): static
+    {
+        $this->disabledReasonInternal = $disabledReasonInternal;
+
+        return $this;
+    }
 }
diff --git a/src/Form/DisableUserType.php b/src/Form/DisableUserType.php
new file mode 100644
index 0000000..f537869
--- /dev/null
+++ b/src/Form/DisableUserType.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace App\Form;
+
+use App\Entity\User;
+use Symfony\Component\Form\AbstractType;
+use Symfony\Component\Form\Extension\Core\Type\TextareaType;
+use Symfony\Component\Form\FormBuilderInterface;
+use Symfony\Component\OptionsResolver\OptionsResolver;
+use Symfony\Component\Validator\Constraints\NotBlank;
+
+class DisableUserType extends AbstractType
+{
+    public function buildForm(FormBuilderInterface $builder, array $options): void
+    {
+        $builder
+            ->add('disabledReason', TextareaType::class, [
+                'label' => 'Begründung',
+                'attr' => [
+                    'data-controller' => 'textarea-autosize',
+                    'data-action' => 'textarea-autosize#resize',
+                ],
+                'constraints' => [
+                    new NotBlank([
+                        'message' => 'Bitte gib die Begründung ein',
+                    ]),
+                ],
+            ])
+            ->add('disabledReasonInternal', TextareaType::class, [
+                'label' => 'Begründung intern',
+                'required' => false,
+                'attr' => [
+                    'data-controller' => 'textarea-autosize',
+                    'data-action' => 'textarea-autosize#resize',
+                ],
+            ])
+        ;
+    }
+
+    public function configureOptions(OptionsResolver $resolver): void
+    {
+        $resolver->setDefaults([
+            'data_class' => User::class,
+        ]);
+    }
+}
diff --git a/src/Security/UserChecker.php b/src/Security/UserChecker.php
new file mode 100644
index 0000000..93baa21
--- /dev/null
+++ b/src/Security/UserChecker.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace App\Security;
+
+use App\Entity\User;
+use Symfony\Component\Security\Core\Exception\CustomUserMessageAccountStatusException;
+use Symfony\Component\Security\Core\User\UserCheckerInterface;
+use Symfony\Component\Security\Core\User\UserInterface;
+
+class UserChecker implements UserCheckerInterface
+{
+    public function checkPreAuth(UserInterface $user): void
+    {
+        if (!$user instanceof User) {
+            return;
+        }
+
+        if (true === $user->isDisabled()) {
+            throw new CustomUserMessageAccountStatusException('Dein Account wurde gesperrt: '.$user->getDisabledReason());
+        }
+    }
+
+    public function checkPostAuth(UserInterface $user): void
+    {
+    }
+}
diff --git a/templates/admin/teamer/modal_disable_user.html.twig b/templates/admin/teamer/modal_disable_user.html.twig
new file mode 100644
index 0000000..7b43483
--- /dev/null
+++ b/templates/admin/teamer/modal_disable_user.html.twig
@@ -0,0 +1,19 @@
+{% extends 'htmx_modal.html.twig' %}
+
+{% block title %}Benutzeraccount sperren{% endblock %}
+
+{% block content %}
+    {{ form_start(form) }}
+    <h2 class="font-bold text-lg pb-4">
+        Teamer:in {{ teamer }}
+    </h2>
+    <div class="flex flex-col space-y-4 pb-4">
+        {{ form_row(form.disabledReason) }}
+        {{ form_row(form.disabledReasonInternal) }}
+    </div>
+    <button type="submit" class="btn bg-red-500 text-white">
+        Sperren
+    </button>
+    {{ form_rest(form) }}
+    {{ form_end(form) }}
+{% endblock %}
diff --git a/templates/admin/teamer/modal_enable_user.html.twig b/templates/admin/teamer/modal_enable_user.html.twig
new file mode 100644
index 0000000..e34148b
--- /dev/null
+++ b/templates/admin/teamer/modal_enable_user.html.twig
@@ -0,0 +1,10 @@
+{% extends 'htmx_confirmation_modal.html.twig' %}
+
+{% block content %}
+    <div class="pb-4">
+        Möchtest du den Benutzeraccount von <em>{{ teamer }}</em> wirklich reaktivieren?
+    </div>
+    <div>
+        Der Grund der Sperrung war: <em>{{ teamer.user.disabledReasonInternal ?? teamer.user.disabledReason }}</em>
+    </div>
+{% endblock %}
diff --git a/templates/administrative/disposition/modal_call_off.html.twig b/templates/administrative/disposition/modal_call_off.html.twig
index 4498e78..0baafa8 100644
--- a/templates/administrative/disposition/modal_call_off.html.twig
+++ b/templates/administrative/disposition/modal_call_off.html.twig
@@ -5,7 +5,7 @@
 {% block content %}
     {{ form_start(form) }}
     <h2 class="font-bold text-lg pb-4">
-        Teamer {{ disposition.teamer }}
+        Teamer:in {{ disposition.teamer }}
     </h2>
     <div class="flex flex-col space-y-4 pb-4">
         {{ form_row(form.calledOffBy) }}
diff --git a/templates/administrative/teamer/index.html.twig b/templates/administrative/teamer/index.html.twig
index cf54d0d..b98850b 100644
--- a/templates/administrative/teamer/index.html.twig
+++ b/templates/administrative/teamer/index.html.twig
@@ -101,15 +101,44 @@
                                         {{ icon('check') }}
                                     </button>
                                 {% endif %}
-                                {% if is_granted('CAN_IMPERSONATE', teamer.user) %}
-                                    <a href="{{ path('app_teamer_index', { '_switch_user': teamer.user.email }) }}" title="Als Teamer:in maskieren">
-                                        {{ icon('mask') }}
-                                    </a>
+                                {% if teamer.user.disabled  %}
+                                    {% if is_granted('ROLE_ADMIN') %}
+                                        <button type="button"
+                                                role="menuitem"
+                                                tabindex="-1"
+                                                hx-get="{{ path('app_admin_teamer_enable_user', { 'uuid': teamer.uuid }) }}"
+                                                hx-target="body"
+                                                hx-swap="beforeend">
+                                            {{ icon('unlocked') }}
+                                        </button>
+                                    {% endif %}
+                                {% else %}
+                                    {% if is_granted('ROLE_ADMIN') %}
+                                        <button type="button"
+                                                class="text-red-500"
+                                                role="menuitem"
+                                                tabindex="-1"
+                                                hx-get="{{ path('app_admin_teamer_disable_user', { 'uuid': teamer.uuid }) }}"
+                                                hx-target="body"
+                                                hx-swap="beforeend">
+                                            {{ icon('locked') }}
+                                        </button>
+                                    {% endif %}
+                                    {% if is_granted('CAN_IMPERSONATE', teamer.user) %}
+                                        <a href="{{ path('app_teamer_index', { '_switch_user': teamer.user.email }) }}" title="Als Teamer:in maskieren">
+                                            {{ icon('mask') }}
+                                        </a>
+                                    {% endif %}
                                 {% endif %}
                                 <a href="{{ path('app_administrative_teamer_profile', { 'uuid': teamer.uuid, 'r': return_url() }) }}" title="Teamer:innenprofil {{ teamer }}">
                                     {{ icon('user') }}
                                 </a>
                             </div>
+                            {% if teamer.user.disabled %}
+                                <div class="py-1 px-2 mt-2 text-xs bg-red-500 text-white">
+                                    gesp. am {{ teamer.user.disabledAt | date('d.m.Y') }}
+                                </div>
+                            {% endif %}
                         </td>
                     </tr>
                 {% else %}