diff --git a/src/eckit/linalg/allocator/BufferAllocator.h b/src/eckit/linalg/allocator/BufferAllocator.h
index e3b04e04a..77d946a2e 100644
--- a/src/eckit/linalg/allocator/BufferAllocator.h
+++ b/src/eckit/linalg/allocator/BufferAllocator.h
@@ -9,6 +9,8 @@
  */
 
 
+#pragma once
+
 #include "eckit/linalg/SparseMatrix.h"
 
 #include "eckit/memory/MemoryBuffer.h"
diff --git a/src/eckit/linalg/allocator/InPlaceAllocator.h b/src/eckit/linalg/allocator/InPlaceAllocator.h
index 355844f82..61f6cbe7f 100644
--- a/src/eckit/linalg/allocator/InPlaceAllocator.h
+++ b/src/eckit/linalg/allocator/InPlaceAllocator.h
@@ -9,6 +9,8 @@
  */
 
 
+#pragma once
+
 #include "eckit/linalg/SparseMatrix.h"
 
 
diff --git a/src/eckit/linalg/allocator/StandardAllocator.h b/src/eckit/linalg/allocator/StandardAllocator.h
index d69c2646e..44915479a 100644
--- a/src/eckit/linalg/allocator/StandardAllocator.h
+++ b/src/eckit/linalg/allocator/StandardAllocator.h
@@ -9,6 +9,8 @@
  */
 
 
+#pragma once
+
 #include "eckit/linalg/SparseMatrix.h"
 
 #include "eckit/memory/MemoryBuffer.h"