diff --git a/sbin/setkey/setkey.8 b/sbin/setkey/setkey.8
index 5861ced56802..cac4af731430 100644
--- a/sbin/setkey/setkey.8
+++ b/sbin/setkey/setkey.8
@@ -403,7 +403,7 @@ as it requires extra reassembly at forwarding node
 (not implemented at this moment).
 We have many protocols in
 .Pa /etc/protocols ,
-but protocols except of TCP, UDP and ICMP may not be suitable to use with IPSec.
+but protocols except of TCP, UDP and ICMP may not be suitable to use with IPsec.
 You have to consider and be careful to use them.
 .Li icmp
 .Li tcp
diff --git a/usr.sbin/setkey/setkey.8 b/usr.sbin/setkey/setkey.8
index 5861ced56802..cac4af731430 100644
--- a/usr.sbin/setkey/setkey.8
+++ b/usr.sbin/setkey/setkey.8
@@ -403,7 +403,7 @@ as it requires extra reassembly at forwarding node
 (not implemented at this moment).
 We have many protocols in
 .Pa /etc/protocols ,
-but protocols except of TCP, UDP and ICMP may not be suitable to use with IPSec.
+but protocols except of TCP, UDP and ICMP may not be suitable to use with IPsec.
 You have to consider and be careful to use them.
 .Li icmp
 .Li tcp