diff --git a/cpp/iterative-inl.h b/cpp/iterative-inl.h
index edfb73e81..6e73d8031 100644
--- a/cpp/iterative-inl.h
+++ b/cpp/iterative-inl.h
@@ -5,6 +5,8 @@
  * Created on: Dec 28, 2009
  */
 
+#pragma once
+
 #include "GaussianFactorGraph.h"
 #include "iterative.h"
 
diff --git a/cpp/iterative.h b/cpp/iterative.h
index ba7b72bfd..dbfbeb6b9 100644
--- a/cpp/iterative.h
+++ b/cpp/iterative.h
@@ -5,6 +5,8 @@
  * Created on: Dec 28, 2009
  */
 
+#pragma once
+
 #include "Matrix.h"
 
 namespace gtsam {