diff --git a/private/sha1.h b/private/sha1.h
index b97659e..b148530 100644
--- a/private/sha1.h
+++ b/private/sha1.h
@@ -18,7 +18,6 @@
 #ifndef CPPCMS_PRIVATE_SHA1_H
 #define CPPCMS_PRIVATE_SHA1_H
 
-#include <boost/static_assert.hpp>
 #include <cstddef>
 
 namespace cppcms {