diff --git a/src/graph/graph_properties.hh b/src/graph/graph_properties.hh
index 11bc15750b416805757e18b420c05ca9dd3dd918..728a03137276daae3333b1a20f4da3f01112a157 100644
--- a/src/graph/graph_properties.hh
+++ b/src/graph/graph_properties.hh
@@ -23,6 +23,7 @@
 #include <vector>
 #include <memory>
 #include <random>
+#include <unordered_map>
 #include <boost/functional/hash.hpp>
 #include <boost/python/object.hpp>
 #include <boost/python/extract.hpp>