diff --git a/i3lock.1 b/i3lock.1
index 8b07229..05a886f 100644
--- a/i3lock.1
+++ b/i3lock.1
@@ -120,6 +120,10 @@ your computer with the enter key.
 .B \-f, \-\-show-failed-attempts
 Show the number of failed attempts, if any.
 
+.TP
+.B \-\-debug
+Enables debug logging.
+
 .SH SEE ALSO
 .IR xautolock(1)
 \- use i3lock as your screen saver