diff --git a/lib/util/ttysize.c b/lib/util/ttysize.c
index 01a9ca27c..85b178455 100644
--- a/lib/util/ttysize.c
+++ b/lib/util/ttysize.c
@@ -23,7 +23,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
-#include <termios.h>
+#include <termios.h>		/* for struct winsize on HP-UX */
 #include <limits.h>
 
 #include "sudo_compat.h"
diff --git a/src/exec_pty.c b/src/exec_pty.c
index f614c9c62..e075a508b 100644
--- a/src/exec_pty.c
+++ b/src/exec_pty.c
@@ -32,6 +32,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
+#include <termios.h>		/* for struct winsize on HP-UX */
 
 #include "sudo.h"
 #include "sudo_event.h"