diff --git a/src/OpenFOAM/containers/HashTables/HashTable/HashTable.H b/src/OpenFOAM/containers/HashTables/HashTable/HashTable.H
index 06635bbac3..cd50551d5d 100644
--- a/src/OpenFOAM/containers/HashTables/HashTable/HashTable.H
+++ b/src/OpenFOAM/containers/HashTables/HashTable/HashTable.H
@@ -57,6 +57,7 @@ SourceFiles
 #include "uLabel.H"
 #include "word.H"
 #include "Xfer.H"
+#include "Hash.H"
 #include "className.H"
 #include "nullObject.H"