diff --git a/src/boundary/ShiftedPeriodicity.h b/src/boundary/ShiftedPeriodicity.h
index ce2a32e550d5524c2f291bf901323211ec12f099..f0e46ce010ed80c96077fd6933e4dc776380b15b 100644
--- a/src/boundary/ShiftedPeriodicity.h
+++ b/src/boundary/ShiftedPeriodicity.h
@@ -19,6 +19,8 @@
 //
 //======================================================================================================================
 
+#pragma once
+
 #include "blockforest/Block.h"
 #include "blockforest/BlockID.h"
 #include "blockforest/StructuredBlockForest.h"
diff --git a/src/gpu/ShiftedPeriodicity.h b/src/gpu/ShiftedPeriodicity.h
index cf46577c21e688aaa375f15eddfd969e4eb6f669..fce8b1343fee4cd1013f906645c07d7d91700cc8 100644
--- a/src/gpu/ShiftedPeriodicity.h
+++ b/src/gpu/ShiftedPeriodicity.h
@@ -19,6 +19,8 @@
 //
 //======================================================================================================================
 
+#pragma once
+
 #include "blockforest/StructuredBlockForest.h"
 
 #include "boundary/ShiftedPeriodicity.h"