diff --git a/include/boost/thread/pthread/pthread_helpers.hpp b/include/boost/thread/pthread/pthread_helpers.hpp
index 680999416..f3447d1fc 100644
--- a/include/boost/thread/pthread/pthread_helpers.hpp
+++ b/include/boost/thread/pthread/pthread_helpers.hpp
@@ -9,6 +9,7 @@
 
 #include <boost/thread/detail/config.hpp>
 #include <boost/throw_exception.hpp>
+#include <boost/assert.hpp>
 #include <pthread.h>
 #include <errno.h>