diff --git a/manager-bundle/composer.json b/manager-bundle/composer.json
index d3055e7361b..57858a8d045 100644
--- a/manager-bundle/composer.json
+++ b/manager-bundle/composer.json
@@ -50,7 +50,7 @@
         "symfony/routing": "4.4.*",
         "symfony/security-bundle": "4.4.*",
         "symfony/stopwatch": "4.4.*",
-        "symfony/swiftmailer-bundle": "^2.6.2 || ^3.1.5",
+        "symfony/swiftmailer-bundle": "^3.2.8",
         "symfony/twig-bundle": "4.4.*",
         "symfony/web-profiler-bundle": "4.4.*",
         "symfony/yaml": "4.4.*",
diff --git a/manager-bundle/src/ContaoManager/Plugin.php b/manager-bundle/src/ContaoManager/Plugin.php
index 0480f72368b..bf2ca173c23 100644
--- a/manager-bundle/src/ContaoManager/Plugin.php
+++ b/manager-bundle/src/ContaoManager/Plugin.php
@@ -245,6 +245,7 @@ public function getExtensionConfig($extensionName, array $extensionConfigs, Plug
 
             case 'swiftmailer':
                 $extensionConfigs = $this->checkMailerTransport($extensionConfigs, $container);
+                $extensionConfigs = $this->setSendmailCommand($extensionConfigs);
 
                 if (!isset($_SERVER['MAILER_URL'])) {
                     $container->setParameter('env(MAILER_URL)', $this->getMailerUrl($container));
@@ -372,6 +373,30 @@ private function getDatabaseUrl(ContainerBuilder $container): string
         );
     }
 
+    /**
+     * Sets the sendmail command for Swiftmailer to the sendmail_path defined by PHP.
+     *
+     * @return array<string,array<string,array<string,array<string,mixed>>>>
+     */
+    private function setSendmailCommand(array $extensionConfigs): array
+    {
+        $sendmailPath = @ini_get('sendmail_path');
+
+        if (!$sendmailPath) {
+            return $extensionConfigs;
+        }
+
+        foreach ($extensionConfigs as $extensionConfig) {
+            if (isset($extensionConfig['command']) || isset($extensionConfig['mailers']['default']['command'])) {
+                return $extensionConfigs;
+            }
+        }
+
+        $extensionConfigs[] = ['command' => $sendmailPath];
+
+        return $extensionConfigs;
+    }
+
     private function getMailerUrl(ContainerBuilder $container): string
     {
         if ('sendmail' === $container->getParameter('mailer_transport')) {
diff --git a/manager-bundle/tests/ContaoManager/PluginTest.php b/manager-bundle/tests/ContaoManager/PluginTest.php
index 023c27fd27f..c25ecf1496c 100644
--- a/manager-bundle/tests/ContaoManager/PluginTest.php
+++ b/manager-bundle/tests/ContaoManager/PluginTest.php
@@ -570,6 +570,46 @@ public function getMailerParameters(): \Generator
         ];
     }
 
+    public function testSetsTheSendmailCommand(): void
+    {
+        $container = $this->getContainer();
+
+        $extensionConfig = (new Plugin())->getExtensionConfig('swiftmailer', [], $container);
+
+        $this->assertTrue(!ini_get('sendmail_path') || isset($extensionConfig[0]['command']));
+    }
+
+    public function testDoesNotSetTheSendmailCommandIfAlreadyDefined(): void
+    {
+        $container = $this->getContainer();
+
+        $extensionConfigs = [[
+            'command' => '/foobar/sendmail -t',
+        ]];
+
+        $expect = $extensionConfigs;
+
+        $extensionConfig = (new Plugin())->getExtensionConfig('swiftmailer', $extensionConfigs, $container);
+
+        $this->assertSame($expect, $extensionConfig);
+
+        $extensionConfigs = [
+            [
+                'mailers' => [
+                    'default' => [
+                        'command' => '/foobar/sendmail -t',
+                    ],
+                ],
+            ],
+        ];
+
+        $expect = $extensionConfigs;
+
+        $extensionConfig = (new Plugin())->getExtensionConfig('swiftmailer', $extensionConfigs, $container);
+
+        $this->assertSame($expect, $extensionConfig);
+    }
+
     public function testRetrievesTheConnectionParametersFromTheConfiguration(): void
     {
         $pluginLoader = $this->createMock(PluginLoader::class);