diff --git a/bin/stty/stty.1 b/bin/stty/stty.1
index 26732d2d6a69..7a5a582712f8 100644
--- a/bin/stty/stty.1
+++ b/bin/stty/stty.1
@@ -462,6 +462,8 @@ characters are set to ^?, ^U, and ^C;
 is disabled, and
 .Dv crt
 is enabled.)
+.It Cm drainwait Ar number
+Set output drain timeout in seconds.
 .It Cm extproc Pq Fl extproc
 If set, this flag indicates that some amount of terminal processing is being
 performed by either the terminal hardware or by the remote side connected