diff --git a/compute/cker/include/cker/train/operation/ReLU6.h b/compute/cker/include/cker/train/operation/ReLU6.h
new file mode 100644
index 00000000000..3016a031a42
--- /dev/null
+++ b/compute/cker/include/cker/train/operation/ReLU6.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2024 Samsung Electronics Co., Ltd. All Rights Reserved
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __NNFW_CKER_TRAIN_OPERATION_RELU6_H__
+#define __NNFW_CKER_TRAIN_OPERATION_RELU6_H__
+
+#include "cker/Shape.h"
+#include "cker/eigen/Utils.h"
+#include <Eigen/Core>
+
+namespace nnfw
+{
+namespace cker
+{
+namespace train
+{
+
+inline void ReLU6Grad(const Shape &output_shape, const float *output_data,
+                      const Shape &incoming_shape, const float *incoming_data,
+                      const Shape &grad_shape, float *grad_data)
+{
+  const auto output_map = MapAsVector(output_data, output_shape);
+  const auto incoming_map = MapAsVector(incoming_data, incoming_shape);
+  auto grad_map = MapAsVector(grad_data, grad_shape);
+
+  if (output_shape != incoming_shape || output_shape != grad_shape)
+    throw std::runtime_error{"cker::ReLU6Grad: Unsupported shape"};
+
+  grad_map.array() =
+    incoming_map.array() *
+    (0.0f < output_map.array() && output_map.array() < 6.0f).template cast<float>();
+}
+
+} // namespace train
+} // namespace cker
+} // namespace nnfw
+
+#endif // __NNFW_CKER_TRAIN_OPERATION_RELU6_H__
diff --git a/compute/cker/src/train/Relu6.test.cc b/compute/cker/src/train/Relu6.test.cc
new file mode 100644
index 00000000000..ca8a3fc226e
--- /dev/null
+++ b/compute/cker/src/train/Relu6.test.cc
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2024 Samsung Electronics Co., Ltd. All Rights Reserved
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cker/operation/ReLU6.h>
+#include <cker/train/operation/ReLU6.h>
+
+#include <gtest/gtest.h>
+#include <gtest/gtest-spi.h>
+#include <vector>
+
+namespace
+{
+
+using namespace nnfw::cker;
+
+template <typename T> class Relu6OpVerifier
+{
+public:
+  void verifyBackward(const std::vector<T> &output, const std::vector<T> &input_bwd,
+                      const std::vector<T> &expected_output_bwd, bool expect_eq = true)
+  {
+    std::vector<T> calc_output_bwd(input_bwd.size()); // calculated output backward
+    train::ReLU6Grad(Shape{static_cast<int>(output.size())}, output.data(),
+                     Shape{static_cast<int>(input_bwd.size())}, input_bwd.data(),
+                     Shape{static_cast<int>(calc_output_bwd.size())}, calc_output_bwd.data());
+
+    if (expect_eq)
+      EXPECT_EQ(expected_output_bwd, calc_output_bwd);
+    else
+      EXPECT_NE(expected_output_bwd, calc_output_bwd);
+  }
+};
+
+} // namespace
+
+TEST(CKer_Operation, ReLU6)
+{
+  {
+    Relu6OpVerifier<float> verifier;
+
+    // clang-format off
+    // std::vector<float> input_fwd         = {-2.0,  -1.0,  2.0,  3.0,  6.0,  7.0};
+    std::vector<float> output_fwd           = { 0.0,   0.0,  2.0,  3.0,  6.0,  6.0};  
+    std::vector<float> input_bwd            = {-0.1,  -0.2,  0.3,  0.4, -0.1,  0.5};
+    std::vector<float> expected_output_bwd  = { 0.0,   0.0,  0.3,  0.4,  0.0,  0.0};
+    // clang-format on
+
+    verifier.verifyBackward(output_fwd, input_bwd, expected_output_bwd);
+  }
+
+  {
+    Relu6OpVerifier<float> verifier;
+
+    // clang-format off
+    // std::vector<float> input_fwd         = { 7.0,   8.0,  4.0, -4.0, -5.0, 10.0};
+    std::vector<float> output_fwd           = { 6.0,   6.0,  4.0,  0.0,  0.0,  6.0};  
+    std::vector<float> input_bwd            = {-6.1,  -3.3,  7.0,  8.4, -9.2,  0.0};
+    std::vector<float> expected_output_bwd  = { 0.0,   0.0,  7.0,  0.0,  0.0,  0.0};
+    // clang-format on
+
+    verifier.verifyBackward(output_fwd, input_bwd, expected_output_bwd);
+  }
+}
+
+TEST(CKer_Operation, neg_ReLU6)
+{
+  {
+    Relu6OpVerifier<float> verifier;
+
+    // clang-format off
+    // std::vector<float> input_fwd         = { 0.0,   2.0,  4.0,  6.0,  8.0, 10.0};
+    std::vector<float> output_fwd           = { 0.0,   2.0,  4.0,  6.0,  6.0,  6.0};  
+    std::vector<float> input_bwd            = { 0.1,   0.2,  0.3,  0.4,  0.5,  0.6};
+    std::vector<float> expected_output_bwd  = { 0.1,   0.2,  0.3,  0.4,  0.5,  0.6};  // wrong value
+    // clang-format on
+
+    verifier.verifyBackward(output_fwd, input_bwd, expected_output_bwd, false);
+  }
+
+  {
+    Relu6OpVerifier<float> verifier;
+
+    // clang-format off
+    // std::vector<float> input_fwd         = { 0.0,   2.0,  4.0,  6.0,  8.0, 10.0};
+    std::vector<float> output_fwd           = { 0.0,   2.0,  4.0,  6.0,  6.0,  6.0};  
+    std::vector<float> input_bwd            = { 0.1,   0.2,  0.3,  0.4};  // size mismatch
+    std::vector<float> expected_output_bwd  = { 0.0,   0.2,  0.3,  0.4};
+    // clang-format on
+
+    EXPECT_ANY_THROW(verifier.verifyBackward(output_fwd, input_bwd, expected_output_bwd, false));
+  }
+}