diff --git a/tests/validation/CPP/FlattenLayer.cpp b/tests/validation/CPP/FlattenLayer.cpp
new file mode 100644
index 0000000..611701d
--- /dev/null
+++ b/tests/validation/CPP/FlattenLayer.cpp
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2017 ARM Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include "FlattenLayer.h"
+
+#include "tests/validation/FixedPoint.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace reference
+{
+template <typename T>
+SimpleTensor<T> flatten_layer(const SimpleTensor<T> &src)
+{
+    TensorShape shape_flatten(src.shape());
+    shape_flatten.set(0, src.shape()[0] * src.shape()[1] * src.shape()[2]);
+    shape_flatten.remove_dimension(1);
+    shape_flatten.remove_dimension(1);
+    SimpleTensor<T> dst(shape_flatten, src.data_type(), 1, src.fixed_point_position());
+
+    // Note: Since the reference implementation does not use padding bytes, we can copy directly the content of the source tensor
+    std::copy(src.data(), src.data() + src.num_elements(), dst.data());
+
+    return dst;
+}
+
+template SimpleTensor<float> flatten_layer(const SimpleTensor<float> &src);
+template SimpleTensor<half> flatten_layer(const SimpleTensor<half> &src);
+template SimpleTensor<qint8_t> flatten_layer(const SimpleTensor<qint8_t> &src);
+template SimpleTensor<qint16_t> flatten_layer(const SimpleTensor<qint16_t> &src);
+} // namespace reference
+} // namespace validation
+} // namespace test
+} // namespace arm_compute