diff --git a/include/boost/spirit/home/classic/core/non_terminal/impl/static.hpp b/include/boost/spirit/home/classic/core/non_terminal/impl/static.hpp
index ae2a66c50..c78365e79 100644
--- a/include/boost/spirit/home/classic/core/non_terminal/impl/static.hpp
+++ b/include/boost/spirit/home/classic/core/non_terminal/impl/static.hpp
@@ -15,7 +15,9 @@
 #include <boost/type_traits/add_pointer.hpp>
 #include <boost/type_traits/alignment_of.hpp>
 
+#ifdef BOOST_DISABLE_THREADS
 #include <boost/thread/once.hpp>
+#endif
 
 #include <memory>   // for placement new
 
@@ -69,7 +71,9 @@ BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
 
         static_(Tag = Tag())
         {
+#ifdef BOOST_DISABLE_THREADS
             boost::call_once(&default_ctor::construct, constructed_);
+#endif
         }
 
         operator reference()
@@ -110,12 +114,14 @@ BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
     template <class T, class Tag>
     typename static_<T, Tag>::storage_type static_<T, Tag>::data_;
 
+#ifdef BOOST_DISABLE_THREADS
     template <class T, class Tag>
 #ifndef BOOST_THREAD_PROVIDES_ONCE_CXX11
     once_flag static_<T, Tag>::constructed_ = BOOST_ONCE_INIT;
 #else
     once_flag static_<T, Tag>::constructed_;
 #endif
+#endif
 
 BOOST_SPIRIT_CLASSIC_NAMESPACE_END