diff --git a/addons/mass_mailing/static/src/scss/mass_mailing.scss b/addons/mass_mailing/static/src/scss/mass_mailing.scss
index 80f4f5d29e2..a3b3f278a62 100644
--- a/addons/mass_mailing/static/src/scss/mass_mailing.scss
+++ b/addons/mass_mailing/static/src/scss/mass_mailing.scss
@@ -11,6 +11,10 @@
     .oe-toolbar {
         margin: 0;
     }
+
+    .o_notebook .o_notebook_headers .nav-link[name="mail_debug"] {
+        display: none;
+    }
 }
 
 @include media-breakpoint-up(lg, $o-extra-grid-breakpoints) {