diff --git a/include/libtorrent/span.hpp b/include/libtorrent/span.hpp
index ddbb5850f..982264e8c 100644
--- a/include/libtorrent/span.hpp
+++ b/include/libtorrent/span.hpp
@@ -33,6 +33,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #ifndef TORRENT_SPAN_HPP_INCLUDED
 #define TORRENT_SPAN_HPP_INCLUDED
 
+#include <string>
 #include <array>
 #include <type_traits>
 #include "libtorrent/assert.hpp"