diff --git a/gtsam/slam/expressions.h b/gtsam/slam/expressions.h
index 7a731d29d..6b7ffdf12 100644
--- a/gtsam/slam/expressions.h
+++ b/gtsam/slam/expressions.h
@@ -9,6 +9,7 @@
 
 #include <gtsam/nonlinear/expressions.h>
 #include <gtsam/geometry/Cal3_S2.h>
+#include <gtsam/geometry/Cal3Bundler.h>
 #include <gtsam/geometry/PinholeCamera.h>
 
 namespace gtsam {