diff --git a/niv/include/niv/testing/conduit_schema.hpp b/niv/include/niv/testing/conduit_schema.hpp
index fc7bad8..76dc7f1 100644
--- a/niv/include/niv/testing/conduit_schema.hpp
+++ b/niv/include/niv/testing/conduit_schema.hpp
@@ -22,6 +22,8 @@
 #ifndef NIV_INCLUDE_NIV_TESTING_CONDUIT_SCHEMA_HPP_
 #define NIV_INCLUDE_NIV_TESTING_CONDUIT_SCHEMA_HPP_
 
+#include <string>
+
 namespace niv {
 namespace testing {
 namespace conduit_schema {