diff --git a/src/Common/ActionResult.php b/src/Common/ActionResult.php
index d9adf77..21a125f 100644
--- a/src/Common/ActionResult.php
+++ b/src/Common/ActionResult.php
@@ -24,7 +24,7 @@ class ActionResult
         return new self(self::STATUS_SUCCESS, $successMessage);
     }
 
-    public static function createErrorResult(string $errorMessage, array $inputData): self
+    public static function createErrorResult(string $errorMessage, ?array $inputData = null): self
     {
         return new self(self::STATUS_ERROR, $errorMessage, $inputData);
     }
diff --git a/src/Common/UserHelper.php b/src/Common/UserHelper.php
index f156459..0607fe3 100644
--- a/src/Common/UserHelper.php
+++ b/src/Common/UserHelper.php
@@ -3,19 +3,21 @@ declare(strict_types=1);
 
 namespace MailAccountAdmin\Common;
 
-use RuntimeException;
+use MailAccountAdmin\Exceptions\UnauthenticatedException;
 use MailAccountAdmin\Models\AdminUser;
 use MailAccountAdmin\Repositories\AdminUserRepository;
 
 class UserHelper
 {
-    private SessionHelper $sessionHelper;
     private AdminUserRepository $adminUserRepository;
+    private SessionHelper $sessionHelper;
+    private PasswordHelper $passwordHelper;
 
-    public function __construct(SessionHelper $sessionHelper, AdminUserRepository $adminUserRepository)
+    public function __construct(AdminUserRepository $adminUserRepository, SessionHelper $sessionHelper, PasswordHelper $passwordHelper)
     {
-        $this->sessionHelper = $sessionHelper;
         $this->adminUserRepository = $adminUserRepository;
+        $this->sessionHelper = $sessionHelper;
+        $this->passwordHelper = $passwordHelper;
     }
 
     public function isLoggedIn(): bool
@@ -27,8 +29,17 @@ class UserHelper
     {
         $userId = $this->sessionHelper->getUserId();
         if (empty($userId)) {
-            throw new RuntimeException('Not logged in!');
+            throw new UnauthenticatedException('Not logged in!');
         }
         return $this->adminUserRepository->getUserById($userId);
     }
+
+    public function confirmActionByAdminPassword(string $enteredPassword): void
+    {
+        $currentUser = $this->getCurrentUser();
+
+        if (!$this->passwordHelper->verifyPassword($enteredPassword, $currentUser->getPasswordHash())) {
+            throw new UnauthenticatedException('Admin password wrong.');
+        }
+    }
 }
diff --git a/src/Dependencies.php b/src/Dependencies.php
index 654bbed..53d21f1 100644
--- a/src/Dependencies.php
+++ b/src/Dependencies.php
@@ -98,8 +98,9 @@ class Dependencies
 
         $container->set(UserHelper::class, function (ContainerInterface $c) {
             return new UserHelper(
-                $c->get(SessionHelper::class),
                 $c->get(AdminUserRepository::class),
+                $c->get(SessionHelper::class),
+                $c->get(PasswordHelper::class),
             );
         });
 
diff --git a/src/Exceptions/UnauthenticatedException.php b/src/Exceptions/UnauthenticatedException.php
new file mode 100644
index 0000000..3dda3ca
--- /dev/null
+++ b/src/Exceptions/UnauthenticatedException.php
@@ -0,0 +1,8 @@
+<?php
+declare(strict_types=1);
+
+namespace MailAccountAdmin\Exceptions;
+
+class UnauthenticatedException extends AppException
+{
+}
diff --git a/src/Frontend/Accounts/AccountController.php b/src/Frontend/Accounts/AccountController.php
index 29a0762..7209067 100644
--- a/src/Frontend/Accounts/AccountController.php
+++ b/src/Frontend/Accounts/AccountController.php
@@ -6,6 +6,7 @@ namespace MailAccountAdmin\Frontend\Accounts;
 use MailAccountAdmin\Common\ActionResult;
 use MailAccountAdmin\Common\SessionHelper;
 use MailAccountAdmin\Common\UserHelper;
+use MailAccountAdmin\Exceptions\AppException;
 use MailAccountAdmin\Exceptions\InputValidationError;
 use MailAccountAdmin\Frontend\BaseController;
 use Psr\Http\Message\ResponseInterface as Response;
@@ -31,7 +32,12 @@ class AccountController extends BaseController
         $queryParams = $request->getQueryParams();
         $filterByDomain = $queryParams['domain'] ?? '';
 
+        // Get list of all accounts
         $renderData = $this->accountHandler->listAccounts($filterByDomain);
+
+        // If the form has been submitted, add the result message to the render data array
+        $renderData = $this->addLastActionResultToRenderData($renderData);
+
         return $this->view->render($response, 'accounts.html.twig', $renderData);
     }
 
@@ -55,10 +61,7 @@ class AccountController extends BaseController
         $renderData = $this->accountHandler->getPageDataForCreate();
 
         // If the form has been submitted, add the result message and form input data to the render data array
-        $lastActionResult = $this->sessionHelper->getLastActionResult();
-        if ($lastActionResult !== null) {
-            $renderData = array_merge($renderData, $lastActionResult->getRenderData());
-        }
+        $renderData = $this->addLastActionResultToRenderData($renderData);
 
         return $this->view->render($response, 'account_create.html.twig', $renderData);
     }
@@ -100,10 +103,7 @@ class AccountController extends BaseController
         $renderData = $this->accountHandler->getAccountDataForEdit($accountId);
 
         // If the form has been submitted, add the result message and form input data to the render data array
-        $lastActionResult = $this->sessionHelper->getLastActionResult();
-        if ($lastActionResult !== null) {
-            $renderData = array_merge($renderData, $lastActionResult->getRenderData());
-        }
+        $renderData = $this->addLastActionResultToRenderData($renderData);
 
         return $this->view->render($response, 'account_edit.html.twig', $renderData);
     }
@@ -145,13 +145,47 @@ class AccountController extends BaseController
         // Get account data and list of aliases from database
         $renderData = $this->accountHandler->getAccountDataForDelete($accountId);
 
+        // If the form has been submitted, add the result message to the render data array
+        $renderData = $this->addLastActionResultToRenderData($renderData);
+
         return $this->view->render($response, 'account_delete.html.twig', $renderData);
     }
 
     public function deleteAccount(Request $request, Response $response, array $args): Response
     {
-        // TODO: just a placeholder
-        $this->view->getEnvironment()->addGlobal('error', 'Not implemented yet!');
-        return $this->showAccountDelete($request, $response, $args);
+        // Parse URL arguments and form data
+        $accountId = (int)$args['id'];
+        $formData = $request->getParsedBody();
+
+        try {
+            // Confirm action by entering the admin password
+            $this->userHelper->confirmActionByAdminPassword($formData['admin_password'] ?? '');
+
+            // Delete account
+            $deleteResult = $this->accountHandler->deleteAccount($accountId);
+
+            // Save success result
+            $successMessage = "Account <i>{$deleteResult['username']}</i> ";
+            $deletedAliasCount = $deleteResult['deleted_alias_count'];
+            if ($deletedAliasCount > 0) {
+                $aliasWordPlural = $deletedAliasCount > 1 ? 'aliases' : 'alias';
+                $successMessage .= "and {$deletedAliasCount} {$aliasWordPlural} were deleted.";
+            } else {
+                $successMessage .= "was deleted.";
+            }
+            $this->sessionHelper->setLastActionResult(ActionResult::createSuccessResult($successMessage));
+
+            // Redirect to account list (where the success message will be displayed)
+            $redirectTarget = '/accounts';
+        } catch (AppException $e) {
+            // Save error result
+            $this->sessionHelper->setLastActionResult(ActionResult::createErrorResult($e->getMessage()));
+
+            // Stay on delete page
+            $redirectTarget = '/accounts/' . $accountId . '/delete';
+        }
+
+        // Redirect to edit form page via GET (PRG)
+        return $response->withHeader('Location', $redirectTarget)->withStatus(303);
     }
 }
diff --git a/src/Frontend/Accounts/AccountHandler.php b/src/Frontend/Accounts/AccountHandler.php
index 4e58e5a..0556e6a 100644
--- a/src/Frontend/Accounts/AccountHandler.php
+++ b/src/Frontend/Accounts/AccountHandler.php
@@ -212,7 +212,7 @@ class AccountHandler
 
         // Remove existing alias for new username (if wanted)
         if ($editData->getUsernameReplaceAlias() && $aliasNeedsToBeReplaced) {
-            $this->aliasRepository->removeAlias($accountId, $newUsername);
+            $this->aliasRepository->deleteAlias($accountId, $newUsername);
         }
 
         // Commit database transaction
@@ -238,4 +238,31 @@ class AccountHandler
             'aliases' => $aliases,
         ];
     }
+
+    public function deleteAccount(int $accountId): array
+    {
+        // Check if account exists
+        try {
+            $account = $this->accountRepository->fetchAccountById($accountId);
+        } catch (AccountNotFoundException $e) {
+            throw new InputValidationError('Account with ID ' . $accountId . ' does not exist!');
+        }
+
+        // Start database transaction
+        $this->accountRepository->beginTransaction();
+
+        // Delete all aliases associated with this account
+        $deleteAliasCount = $this->aliasRepository->deleteAllAliasesForUserId($accountId);
+
+        // Delete account from database
+        $this->accountRepository->deleteAccountWithId($accountId);
+
+        // Commit database transaction
+        $this->accountRepository->commitTransaction();
+
+        return [
+            'username' => $account->getUsername(),
+            'deleted_alias_count' => $deleteAliasCount,
+        ];
+    }
 }
diff --git a/src/Frontend/BaseController.php b/src/Frontend/BaseController.php
index 278fb2e..eadc069 100644
--- a/src/Frontend/BaseController.php
+++ b/src/Frontend/BaseController.php
@@ -23,4 +23,13 @@ class BaseController
         $twigEnv = $view->getEnvironment();
         $twigEnv->addGlobal('current_user_name', $userHelper->isLoggedIn() ? $userHelper->getCurrentUser()->getUsername() : null);
     }
+
+    protected function addLastActionResultToRenderData(array $renderData): array
+    {
+        $lastActionResult = $this->sessionHelper->getLastActionResult();
+        if ($lastActionResult !== null) {
+            $renderData = array_merge($renderData, $lastActionResult->getRenderData());
+        }
+        return $renderData;
+    }
 }
diff --git a/src/Repositories/AccountRepository.php b/src/Repositories/AccountRepository.php
index 318ada1..f66a5ca 100644
--- a/src/Repositories/AccountRepository.php
+++ b/src/Repositories/AccountRepository.php
@@ -124,4 +124,10 @@ class AccountRepository extends BaseRepository
         $statement = $this->pdo->prepare($query);
         $statement->execute($queryParams);
     }
+
+    public function deleteAccountWithId(int $accountId): void
+    {
+        $statement = $this->pdo->prepare('DELETE FROM mail_users WHERE user_id = :user_id LIMIT 1');
+        $statement->execute(['user_id' => $accountId]);
+    }
 }
diff --git a/src/Repositories/AliasRepository.php b/src/Repositories/AliasRepository.php
index 91bea5b..86b9caf 100644
--- a/src/Repositories/AliasRepository.php
+++ b/src/Repositories/AliasRepository.php
@@ -52,7 +52,7 @@ class AliasRepository extends BaseRepository
         ]);
     }
 
-    public function removeAlias(int $userId, string $mailAddress): void
+    public function deleteAlias(int $userId, string $mailAddress): void
     {
         // Check user ID in WHERE clause to make sure we don't accidentally delete someone else's alias
         $statement = $this->pdo->prepare('DELETE FROM mail_aliases WHERE user_id = :user_id AND mail_address = :mail_address LIMIT 1');
@@ -61,4 +61,13 @@ class AliasRepository extends BaseRepository
             'mail_address' => $mailAddress,
         ]);
     }
+
+    public function deleteAllAliasesForUserId(int $userId): int
+    {
+        $statement = $this->pdo->prepare('DELETE FROM mail_aliases WHERE user_id = :user_id');
+        $statement->execute([
+            'user_id' => $userId,
+        ]);
+        return $statement->rowCount();
+    }
 }
diff --git a/templates/account_delete.html.twig b/templates/account_delete.html.twig
index 6b0f949..927698e 100644
--- a/templates/account_delete.html.twig
+++ b/templates/account_delete.html.twig
@@ -15,21 +15,16 @@
 
     <h3>Delete account</h3>
 
-    <p>You are about to delete the mail account "{{ accountUsername }}" including the following aliases:</p>
+    <p>You are about to delete the mail account "{{ accountUsername }}" <b>including</b> the following aliases:</p>
     <ul>
         {% for alias in aliases %}
             <li>{{ alias.getMailAddress() }}</li>
         {% endfor %}
     </ul>
 
-    <p><b>Note:</b> This will only delete the user entry from the database. Mail data will not be deleted!</p>
+    <p><b>Note:</b> This will only delete the account entry from the database. Mail data will not be deleted!</p>
 
-    {% if error is defined %}
-        <div class="error_box">
-            <h4>Error:</h4>
-            {{ error }}
-        </div>
-    {% endif %}
+    {{ include('includes/form_result_box.html.twig') }}
 
     <div class="confirmation_box">
         <p><b>Please confirm that you want to delete this account by entering your password.</b></p>
diff --git a/templates/accounts.html.twig b/templates/accounts.html.twig
index ae99225..9f5086c 100644
--- a/templates/accounts.html.twig
+++ b/templates/accounts.html.twig
@@ -13,6 +13,8 @@
 
     <h3>List of accounts</h3>
 
+    {{ include('includes/form_result_box.html.twig') }}
+
     <div class="filter_options">
         <form action="/accounts" method="GET">
             <h4>Filter:</h4>