diff --git a/ai_edge_quantizer/qtyping.py b/ai_edge_quantizer/qtyping.py
index 6d5c320..71d83df 100644
--- a/ai_edge_quantizer/qtyping.py
+++ b/ai_edge_quantizer/qtyping.py
@@ -120,6 +120,8 @@ class UniformQuantParams:
     zero_point: The zero point of the quantization.
     symmetric: Whether the quantization is symmetric (force zero_point to be 0).
     quantized_data: The quantized data.
+    block_size: The block size for blockwise quantization, block_size=0 meaning
+      no blockwise quantization.
   """
 
   num_bits: int
@@ -128,6 +130,7 @@ class UniformQuantParams:
   zero_point: np.ndarray
   symmetric: bool = True
   quantized_data: Optional[np.ndarray] = None
+  block_size: int = 0
 
   @classmethod
   def from_tfl_tensor_details(cls, tensor_detail) -> 'UniformQuantParams':
@@ -170,6 +173,7 @@ def __eq__(self, other):
         and np.array_equal(self.zero_point, other.zero_point)
         and self.symmetric == other.symmetric
         and _compare_array_or_none(self.quantized_data, other.quantized_data)
+        and self.block_size == other.block_size
     )
 
 
diff --git a/ai_edge_quantizer/transformations/quantize_tensor.py b/ai_edge_quantizer/transformations/quantize_tensor.py
index 933d960..094fb3c 100644
--- a/ai_edge_quantizer/transformations/quantize_tensor.py
+++ b/ai_edge_quantizer/transformations/quantize_tensor.py
@@ -121,29 +121,54 @@ def quantize_tensor(
       )
 
   if isinstance(transformation_input.quant_params, qtyping.UniformQuantParams):
-    flatbuffer_quantization = schema_py_generated.QuantizationParametersT()
-    flatbuffer_quantization.scale = list(
-        transformation_input.quant_params.scale.flatten().astype(np.float32)
-    )  # flatbuffer requires scale as list[float]
-    flatbuffer_quantization.zeroPoint = list(
-        transformation_input.quant_params.zero_point.flatten().astype(np.int64)
-    )  # flatbuffer requires zeroPoint as list[int64]
-    if transformation_input.quant_params.quantized_dimension is not None:
-      flatbuffer_quantization.quantizedDimension = (
-          transformation_input.quant_params.quantized_dimension
+    if transformation_input.quant_params.block_size == 0:
+      flatbuffer_quantization = schema_py_generated.QuantizationParametersT()
+      flatbuffer_quantization.scale = list(
+          transformation_input.quant_params.scale.flatten().astype(np.float32)
+      )  # flatbuffer requires scale as list[float]
+      if transformation_input.quant_params.zero_point is not None:
+        flatbuffer_quantization.zeroPoint = list(
+            transformation_input.quant_params.zero_point.flatten().astype(
+                np.int64
+            )
+        )  # flatbuffer requires zeroPoint as list[int64]
+      if transformation_input.quant_params.quantized_dimension is not None:
+        flatbuffer_quantization.quantizedDimension = (
+            transformation_input.quant_params.quantized_dimension
+        )
+    else:
+      flatbuffer_quantization = schema_py_generated.QuantizationParametersT()
+      flatbuffer_quantization.detailsType = (
+          schema_py_generated.QuantizationDetails.BlockwiseQuantization
       )
+      blockwise_details = (
+          schema_py_generated.BlockwiseQuantizationT()
+      )
+      scale_tensor_id = transformation_utils.add_new_constant_tensor(
+          tensor.name + b"_scale",
+          transformation_input.quant_params.scale,
+          schema_py_generated.TensorType.FLOAT16,
+          transformation_input.subgraph,
+          transformation_input.buffers,
+      )
+      blockwise_details.scale = scale_tensor_id
+      blockwise_details.blockSize = (
+          transformation_input.quant_params.block_size
+      )
+      if transformation_input.quant_params.zero_point is not None:
+        zero_point_tensor_id = transformation_utils.add_new_constant_tensor(
+            tensor.name + b"_zero_point",
+            transformation_input.quant_params.zero_point,
+            schema_py_generated.TensorType.INT32,
+            transformation_input.subgraph,
+            transformation_input.buffers,
+        )
+        blockwise_details.zeroPoint = zero_point_tensor_id
+      flatbuffer_quantization.details = blockwise_details
     tensor.quantization = flatbuffer_quantization
     tensor.type = quant_params_to_tflite_type(
         transformation_input.quant_params.num_bits
     )
-
-  if isinstance(
-      transformation_input.quant_params, qtyping.NonLinearQuantParams
-  ):
-    tensor.type = nonlinear_quant_params_to_tflite_type(
-        transformation_input.quant_params.num_bits
-    )
-
   if isinstance(
       transformation_input.quant_params, qtyping.NonLinearQuantParams
   ):
diff --git a/ai_edge_quantizer/transformations/quantize_tensor_test.py b/ai_edge_quantizer/transformations/quantize_tensor_test.py
index ee048e1..3cd8c41 100644
--- a/ai_edge_quantizer/transformations/quantize_tensor_test.py
+++ b/ai_edge_quantizer/transformations/quantize_tensor_test.py
@@ -135,6 +135,39 @@ def test_quantize_tensor_with_nonlinear_quantization(self):
         subgraph.tensors[4].type, schema_py_generated.TensorType.FLOAT16
     )
 
+  def test_blockwise_quantization_with_zero_point(self):
+    """test quantizing an activation tensor with blockwise quantization."""
+    subgraph = self._model.subgraphs[0]
+    model = self._model
+    data = np.ones([1, 112, 112, 32]).astype(np.int8)
+    quantize_tensor.quantize_tensor(
+        transformation_utils.TransformationInput(
+            7,
+            model.operatorCodes,
+            model.buffers,
+            subgraph,
+            1,
+            [3],
+            qtyping.UniformQuantParams(
+                8,
+                None,
+                np.ones([1, 112, 112, 1]).astype(np.float16),
+                np.zeros([1, 112, 112, 1]),
+                symmetric=True,
+                quantized_data=data,
+                block_size=32,
+            ),
+        )
+    )
+    quant_param = subgraph.tensors[7].quantization
+    self.assertEqual(
+        quant_param.detailsType,
+        schema_py_generated.QuantizationDetails.BlockwiseQuantization,
+    )
+    self.assertEqual(quant_param.details.blockSize, 32)
+    self.assertEqual(quant_param.details.zeroPoint, 10)
+    self.assertEqual(quant_param.details.scale, 9)
+
   def test_int4_constant_packed_correctly(self):
     subgraph = self._model.subgraphs[0]
     model = self._model