diff --git a/modules/system/models/mailtemplate/fields.yaml b/modules/system/models/mailtemplate/fields.yaml
index 81a316d77..1e4235310 100644
--- a/modules/system/models/mailtemplate/fields.yaml
+++ b/modules/system/models/mailtemplate/fields.yaml
@@ -34,6 +34,7 @@ secondaryTabs:
         content_html:
             type: codeeditor
             size: giant
+            language: html
             tab: system::lang.mail_templates.content_html
 
         content_text: