diff --git a/gtsam/nonlinear/NonlinearEquality.h b/gtsam/nonlinear/NonlinearEquality.h
index 8f2db79fa..4b47e133e 100644
--- a/gtsam/nonlinear/NonlinearEquality.h
+++ b/gtsam/nonlinear/NonlinearEquality.h
@@ -21,6 +21,8 @@
 #include <iostream>
 
 #include <gtsam/nonlinear/NonlinearFactor.h>
+#include <gtsam/base/Testable.h>
+#include <gtsam/base/Manifold.h>
 
 namespace gtsam {