diff --git a/Grid/GridStd.h b/Grid/GridStd.h
index 097e62ab..16cfcf50 100644
--- a/Grid/GridStd.h
+++ b/Grid/GridStd.h
@@ -7,6 +7,7 @@
 #include <cassert>
 #include <complex>
 #include <vector>
+#include <array>
 #include <string>
 #include <iostream>
 #include <iomanip>