diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index e0ee139b367..16f076c7fa2 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4145,6 +4145,7 @@ FROM pg_stat_activity;
         longer than <xref linkend="guc-deadlock-timeout"> to acquire a
         lock.  This is useful in determining if lock waits are causing
         poor performance.  The default is <literal>off</>.
+        Only superusers can change this setting.
        </para>
       </listitem>
      </varlistentry>