diff --git a/usr.bin/truss/truss.h b/usr.bin/truss/truss.h
index 0f58bd8583b9..5a57de7003c1 100644
--- a/usr.bin/truss/truss.h
+++ b/usr.bin/truss/truss.h
@@ -51,7 +51,7 @@ struct procabi {
 
 /*
  * This is confusingly named.  It holds per-thread state about the
- * currently executing system call.  syscalls.h defines a struct
+ * currently executing system call.  syscall.h defines a struct
  * syscall that holds metadata used to format system call arguments.
  *
  * NB: args[] stores the raw argument values (e.g. from registers)