diff --git a/sbin/sysctl/sysctl.8 b/sbin/sysctl/sysctl.8
index 5adc2fcc0f19..bd5f1f254aa0 100644
--- a/sbin/sysctl/sysctl.8
+++ b/sbin/sysctl/sysctl.8
@@ -228,6 +228,10 @@ definitions for fourth level ICMP identifiers
 .It Aq Pa netinet/udp_var.h
 definitions for fourth level UDP identifiers
 .El
+.Sh COMPATIBILITY
+The
+.Fl w
+option has been deprecated and is silently ignored.
 .Sh SEE ALSO
 .Xr sysctl 3 ,
 .Xr sysctl.conf 5