diff --git a/NumLib/Extrapolation/ExtrapolatableElement.h b/NumLib/Extrapolation/ExtrapolatableElement.h
index 3a24dc3fdbcf6a653e19325bec9f2adaa8f5ed53..4a231fc49013b2faf9e3caddc0fc7ebfbb734801 100644
--- a/NumLib/Extrapolation/ExtrapolatableElement.h
+++ b/NumLib/Extrapolation/ExtrapolatableElement.h
@@ -10,6 +10,8 @@
 #ifndef NUMLIB_EXTRAPOLATION_EXTRAPOLATABLEELEMENT_H
 #define NUMLIB_EXTRAPOLATION_EXTRAPOLATABLEELEMENT_H
 
+#include <Eigen/Core>
+
 namespace NumLib
 {
 /*! Interface for providing shape matrices and integration point values for