diff --git a/gtsam/nonlinear/NonlinearOptimization.h b/gtsam/nonlinear/NonlinearOptimization.h
index 6521ded8e..1d134688e 100644
--- a/gtsam/nonlinear/NonlinearOptimization.h
+++ b/gtsam/nonlinear/NonlinearOptimization.h
@@ -18,6 +18,7 @@
 
 #pragma once
 
+#include <gtsam/nonlinear/Values.h>
 #include <gtsam/nonlinear/NonlinearOptimizationParameters.h>
 
 namespace gtsam {