diff --git a/gtsam/constraint/NonlinearConstraint.h b/gtsam/constraint/NonlinearConstraint.h
index 7ee7ed771..da13f77c6 100644
--- a/gtsam/constraint/NonlinearConstraint.h
+++ b/gtsam/constraint/NonlinearConstraint.h
@@ -19,6 +19,7 @@
 #pragma once
 
 #include <gtsam/inference/FactorGraph.h>
+#include <gtsam/inference/FactorGraph-inst.h>
 #include <gtsam/nonlinear/NonlinearFactor.h>
 #ifdef GTSAM_ENABLE_BOOST_SERIALIZATION
 #include <boost/serialization/base_object.hpp>
diff --git a/gtsam/constraint/NonlinearEqualityConstraint.cpp b/gtsam/constraint/NonlinearEqualityConstraint.cpp
index 8705f7db9..170f2317c 100644
--- a/gtsam/constraint/NonlinearEqualityConstraint.cpp
+++ b/gtsam/constraint/NonlinearEqualityConstraint.cpp
@@ -16,6 +16,7 @@
  * @date    Aug 3, 2024 */
 
 #include <gtsam/constraint/NonlinearEqualityConstraint.h>
+#include <gtsam/inference/FactorGraph-inst.h>
 
 namespace gtsam {
 
diff --git a/gtsam/constraint/NonlinearInequalityConstraint.cpp b/gtsam/constraint/NonlinearInequalityConstraint.cpp
index 3404a143c..2f96f9a29 100644
--- a/gtsam/constraint/NonlinearInequalityConstraint.cpp
+++ b/gtsam/constraint/NonlinearInequalityConstraint.cpp
@@ -17,6 +17,7 @@
  */
 
 #include <gtsam/constraint/NonlinearInequalityConstraint.h>
+#include <gtsam/inference/FactorGraph-inst.h>
 
 namespace gtsam {