diff --git a/include/nlohmann/detail/hash.hpp b/include/nlohmann/detail/hash.hpp
index 70c5daf33..b01de59de 100644
--- a/include/nlohmann/detail/hash.hpp
+++ b/include/nlohmann/detail/hash.hpp
@@ -5,6 +5,7 @@
 #include <functional> // hash
 
 #include <nlohmann/detail/macro_scope.hpp>
+#include <nlohmann/detail/value_t.hpp>
 
 namespace nlohmann
 {