diff --git a/core/modules/system/src/Form/SiteInformationForm.php b/core/modules/system/src/Form/SiteInformationForm.php
index 4e4e1571fd..eeb9028c8e 100644
--- a/core/modules/system/src/Form/SiteInformationForm.php
+++ b/core/modules/system/src/Form/SiteInformationForm.php
@@ -110,6 +110,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       '#title' => t('Slogan'),
       '#default_value' => $site_config->get('slogan'),
       '#description' => t("How this is used depends on your site's theme."),
+      '#maxlength' => 256,
     ];
     $form['site_information']['site_mail'] = [
       '#type' => 'email',