diff --git a/src/backends/reference/test/RefPerAxisIteratorTests.cpp b/src/backends/reference/test/RefPerAxisIteratorTests.cpp
index 92b828e..d437f4d 100644
--- a/src/backends/reference/test/RefPerAxisIteratorTests.cpp
+++ b/src/backends/reference/test/RefPerAxisIteratorTests.cpp
@@ -5,6 +5,8 @@
 
 #include <reference/workloads/Decoders.hpp>
 
+#include <armnn/utility/IgnoreUnused.hpp>
+
 #include <fmt/format.h>
 
 #include <doctest/doctest.h>