diff --git a/gtsam/geometry/SOn.h b/gtsam/geometry/SOn.h
index 74b7b8521..f44c578cc 100644
--- a/gtsam/geometry/SOn.h
+++ b/gtsam/geometry/SOn.h
@@ -30,9 +30,6 @@
 #include <vector>
 #include <random>
 
- // For save/load
-#include <boost/serialization/split_member.hpp>
-
 namespace gtsam {
 
 namespace internal {