diff --git a/doc/guix.texi b/doc/guix.texi
index 746561ed97..a934626e5a 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -13988,6 +13988,9 @@ When @code{auto-login?} is false, GDM presents a log-in screen.
 When @code{auto-login?} is true, GDM logs in directly as
 @code{default-user}.
 
+@item @code{debug?} (default: @code{#f})
+When true, GDM writes debug messages to its log.
+
 @item @code{gnome-shell-assets} (default: ...)
 List of GNOME Shell assets needed by GDM: icon theme, fonts, etc.
 
diff --git a/gnu/services/xorg.scm b/gnu/services/xorg.scm
index 1d55e388a1..9c84f7413f 100644
--- a/gnu/services/xorg.scm
+++ b/gnu/services/xorg.scm
@@ -835,6 +835,7 @@ (define-record-type* <gdm-configuration>
   (allow-empty-passwords? gdm-configuration-allow-empty-passwords? (default #t))
   (auto-login? gdm-configuration-auto-login? (default #f))
   (dbus-daemon gdm-configuration-dbus-daemon (default dbus-daemon-wrapper))
+  (debug? gdm-configuration-debug? (default #f))
   (default-user gdm-configuration-default-user (default #f))
   (gnome-shell-assets gdm-configuration-gnome-shell-assets
                       (default (list adwaita-icon-theme font-cantarell)))
@@ -866,7 +867,9 @@ (define (gdm-configuration-file config)
                    "WaylandEnable=false\n"
                    "\n"
                    "[debug]\n"
-                   "#Enable=true\n"
+                   "Enable=" (if (gdm-configuration-debug? config)
+                                 "true"
+                                 "false") "\n"
                    "\n"
                    "[security]\n"
                    "#DisallowTCP=true\n"