diff --git a/libserialport.h.in b/libserialport.h.in
index e4109a9..85fd098 100644
--- a/libserialport.h.in
+++ b/libserialport.h.in
@@ -64,8 +64,8 @@
  * or where otherwise documented a positive value.
  */
 
-#ifndef LIBSERIALPORT_H
-#define LIBSERIALPORT_H
+#ifndef LIBSERIALPORT_LIBSERIALPORT_H
+#define LIBSERIALPORT_LIBSERIALPORT_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -630,4 +630,4 @@ void sp_free_error_message(char *message);
 }
 #endif
 
-#endif /* LIBSERIALPORT_H */
+#endif
diff --git a/linux_termios.h b/linux_termios.h
index 1e1c7d7..cb2ed9d 100644
--- a/linux_termios.h
+++ b/linux_termios.h
@@ -17,6 +17,9 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifndef LIBSERIALPORT_LINUX_TERMIOS_H
+#define LIBSERIALPORT_LINUX_TERMIOS_H
+
 #define RTS_FLOW 1
 #define CTS_FLOW 2
 #define DTR_FLOW 4
@@ -30,3 +33,5 @@ void set_termios_speed(void *data, int speed);
 int get_termiox_size(void);
 int get_termiox_flow(void *data);
 void set_termiox_flow(void *data, int flags);
+
+#endif