diff --git a/include/boost/config/platform/bsd.hpp b/include/boost/config/platform/bsd.hpp
index e83b6433..4f04ed2a 100644
--- a/include/boost/config/platform/bsd.hpp
+++ b/include/boost/config/platform/bsd.hpp
@@ -46,7 +46,9 @@
 //
 // The BSD <ctype.h> has macros only, no functions:
 //
-#define BOOST_NO_CTYPE_FUNCTIONS
+#if !defined(__OpenBSD__)
+#  define BOOST_NO_CTYPE_FUNCTIONS
+#endif
 
 //
 // thread API's not auto detected: