diff --git a/python/gtsam/preamble/nonlinear.h b/python/gtsam/preamble/nonlinear.h
index b50059a2e..d07a75f6f 100644
--- a/python/gtsam/preamble/nonlinear.h
+++ b/python/gtsam/preamble/nonlinear.h
@@ -10,6 +10,3 @@
  * Without this they will be automatically converted to a Python object, and all
  * mutations on Python side will not be reflected on C++.
  */
-#include <pybind11/stl.h>
-
-PYBIND11_MAKE_OPAQUE(std::vector<size_t>);