diff --git a/tests/validation/reference/ActivationLayer.h b/tests/validation/reference/ActivationLayer.h
index cd861d7..f41e871 100644
--- a/tests/validation/reference/ActivationLayer.h
+++ b/tests/validation/reference/ActivationLayer.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2019 ARM Limited.
+ * Copyright (c) 2017-2020 ARM Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -81,6 +81,9 @@
         case ActivationLayerInfo::ActivationFunction::IDENTITY:
             ret = x;
             break;
+        case ActivationLayerInfo::ActivationFunction::HARD_SWISH:
+            ret = x * ((std::min(std::max((x + 3), 0.0f), 6.0f)) * 0.166666667f);
+            break;
         default:
             ARM_COMPUTE_ERROR("Unsupported activation function");
             break;