diff --git a/include/boost/python/object/instance.hpp b/include/boost/python/object/instance.hpp
index 27b91a1e5f..ffc6511909 100644
--- a/include/boost/python/object/instance.hpp
+++ b/include/boost/python/object/instance.hpp
@@ -18,7 +18,7 @@ namespace boost { namespace python { namespace objects {
 
 // Each extension instance will be one of these
 template <class Data = char>
-struct instance
+struct BOOST_PYTHON_DECL instance
 {
     PyObject_VAR_HEAD
     PyObject* dict;