diff --git a/gtsam_unstable/slam/AHRS.h b/gtsam_unstable/slam/AHRS.h
index 35b4677d5..714e62288 100644
--- a/gtsam_unstable/slam/AHRS.h
+++ b/gtsam_unstable/slam/AHRS.h
@@ -5,8 +5,7 @@
  *      Author: cbeall3
  */
 
-#ifndef AHRS_H_
-#define AHRS_H_
+#pragma once
 
 #include "Mechanization_bRn2.h"
 #include <gtsam_unstable/dllexport.h>
@@ -82,4 +81,3 @@ public:
 };
 
 } /* namespace gtsam */
-#endif /* AHRS_H_ */
diff --git a/wrap/pybind11/tests/object.h b/wrap/pybind11/tests/object.h
index 9235f19c2..9fbbc69f0 100644
--- a/wrap/pybind11/tests/object.h
+++ b/wrap/pybind11/tests/object.h
@@ -1,5 +1,4 @@
-#if !defined(__OBJECT_H)
-#define __OBJECT_H
+#pragma once
 
 #include <atomic>
 #include "constructor_stats.h"
@@ -171,5 +170,3 @@ public:
 private:
     T *m_ptr;
 };
-
-#endif /* __OBJECT_H */