diff --git a/include/boost/python/operators.hpp b/include/boost/python/operators.hpp
index 3851b494..e929779e 100644
--- a/include/boost/python/operators.hpp
+++ b/include/boost/python/operators.hpp
@@ -18,6 +18,7 @@
 # include <boost/python/other.hpp>
 # include <boost/lexical_cast.hpp>
 # include <boost/python/refcount.hpp>
+# include <boost/python/detail/unwrap_wrapper.hpp>
 # include <string>
 # include <complex>