diff --git a/gtsam/inference/BayesTree.h b/gtsam/inference/BayesTree.h
index 7199da0ad..cc003d8dc 100644
--- a/gtsam/inference/BayesTree.h
+++ b/gtsam/inference/BayesTree.h
@@ -19,6 +19,8 @@
 
 #pragma once
 
+#include <boost/shared_ptr.hpp>
+
 #include <gtsam/inference/Key.h>
 #include <gtsam/base/FastList.h>
 #include <gtsam/base/ConcurrentMap.h>
diff --git a/gtsam/inference/Factor.h b/gtsam/inference/Factor.h
index 6ea81030a..c0ea4ea78 100644
--- a/gtsam/inference/Factor.h
+++ b/gtsam/inference/Factor.h
@@ -22,6 +22,7 @@
 #pragma once
 
 #include <boost/serialization/nvp.hpp>
+#include <boost/shared_ptr.hpp>
 
 #include <gtsam/base/types.h>
 #include <gtsam/base/FastVector.h>