diff --git a/Classes/Form/FormDefinitionDecorator.php b/Classes/Form/FormDefinitionDecorator.php
index 26eadf6..8cd747b 100644
--- a/Classes/Form/FormDefinitionDecorator.php
+++ b/Classes/Form/FormDefinitionDecorator.php
@@ -41,6 +41,7 @@ protected function overrideDefinition(array $decorated, array $definition, int $
             $this->setNotEmptyValidationErrorMessages($element);
             $this->setCheckboxLinks($element);
             $this->setFileSizeValidatorBytes($element);
+            $this->setMimeTypeValidator($element);
         }
         return $decorated;
     }
@@ -104,4 +105,23 @@ private function setFileSizeValidatorBytes(array &$element): void
             }
         }
     }
+
+    /**
+     * @param mixed[] $element
+     */
+    private function setMimeTypeValidator(array &$element): void
+    {
+        if ($element['type'] === 'FileUpload') {
+            $mimeTypes = $element['properties']['allowedMimeTypes'] ?? [];
+
+            if (!empty($mimeTypes)) {
+                $element['validators'][] = [
+                    'identifier' => 'MimeType',
+                    'options' => [
+                        'allowed' => $mimeTypes,
+                    ],
+                ];
+            }
+        }
+    }
 }