diff --git a/erb/cpp03_define_map.hpp.erb b/erb/cpp03_define_map.hpp.erb
index e33e7785..d94665c5 100644
--- a/erb/cpp03_define_map.hpp.erb
+++ b/erb/cpp03_define_map.hpp.erb
@@ -24,7 +24,10 @@
 // http://www.boost.org/libs/preprocessor/doc/ref/variadics.html
 // However, supporting compiler detection is not complete. msgpack-c requires
 // variadic macro arguments support. So BOOST_PP_VARIADICS is defined here explicitly.
+#if !defined(BOOST_PP_VARIADICS)
 #define BOOST_PP_VARIADICS
+#endif
+
 #include <boost/preprocessor.hpp>
 
 #include "msgpack/versioning.hpp"
diff --git a/include/msgpack/adaptor/detail/cpp03_define_map.hpp b/include/msgpack/adaptor/detail/cpp03_define_map.hpp
index d0ebc9ac..2d29bea9 100644
--- a/include/msgpack/adaptor/detail/cpp03_define_map.hpp
+++ b/include/msgpack/adaptor/detail/cpp03_define_map.hpp
@@ -24,7 +24,10 @@
 // http://www.boost.org/libs/preprocessor/doc/ref/variadics.html
 // However, supporting compiler detection is not complete. msgpack-c requires
 // variadic macro arguments support. So BOOST_PP_VARIADICS is defined here explicitly.
+#if !defined(BOOST_PP_VARIADICS)
 #define BOOST_PP_VARIADICS
+#endif
+
 #include <boost/preprocessor.hpp>
 
 #include "msgpack/versioning.hpp"
diff --git a/include/msgpack/adaptor/detail/cpp11_define_map.hpp b/include/msgpack/adaptor/detail/cpp11_define_map.hpp
index 4fd33b68..fb589e6b 100644
--- a/include/msgpack/adaptor/detail/cpp11_define_map.hpp
+++ b/include/msgpack/adaptor/detail/cpp11_define_map.hpp
@@ -24,7 +24,10 @@
 // http://www.boost.org/libs/preprocessor/doc/ref/variadics.html
 // However, supporting compiler detection is not complete. msgpack-c requires
 // variadic macro arguments support. So BOOST_PP_VARIADICS is defined here explicitly.
+#if !defined(BOOST_PP_VARIADICS)
 #define BOOST_PP_VARIADICS
+#endif
+
 #include <boost/preprocessor.hpp>
 
 #include "msgpack/versioning.hpp"