diff --git a/onnxruntime/python/tools/quantization/calibrate.py b/onnxruntime/python/tools/quantization/calibrate.py
index 74d064204ecca..533b2197bf30c 100644
--- a/onnxruntime/python/tools/quantization/calibrate.py
+++ b/onnxruntime/python/tools/quantization/calibrate.py
@@ -69,6 +69,7 @@ class TensorData:
     _floats = frozenset(["avg", "std", "lowest", "highest", "hist_edges"])
 
     def __init__(self, **kwargs):
+        self._attrs = list(kwargs.keys())
         for k, v in kwargs.items():
             if k not in TensorData._allowed:
                 raise ValueError(f"Unexpected value {k!r} not in {TensorData._allowed}.")
@@ -91,6 +92,12 @@ def avg_std(self):
             raise AttributeError(f"Attributes 'avg' and/or 'std' missing in {dir(self)}.")
         return (self.avg, self.std)
 
+    def to_dict(self):
+        # This is needed to serialize the data into JSON.
+        data = {k: getattr(self, k) for k in self._attrs}
+        data["CLS"] = self.__class__.__name__
+        return data
+
 
 class TensorsData:
     def __init__(self, calibration_method, data: Dict[str, Union[TensorData, Tuple]]):
@@ -125,12 +132,24 @@ def __setitem__(self, key, value):
             raise RuntimeError(f"Only an existing tensor can be modified, {key!r} is not.")
         self.data[key] = value
 
+    def keys(self):
+        return self.data.keys()
+
     def values(self):
         return self.data.values()
 
     def items(self):
         return self.data.items()
 
+    def to_dict(self):
+        # This is needed to serialize the data into JSON.
+        data = {
+            "CLS": self.__class__.__name__,
+            "data": self.data,
+            "calibration_method": self.calibration_method,
+        }
+        return data
+
 
 class CalibrationMethod(Enum):
     MinMax = 0
diff --git a/onnxruntime/python/tools/quantization/quant_utils.py b/onnxruntime/python/tools/quantization/quant_utils.py
index 0fdef4ef6f6d3..9228ad33130f2 100644
--- a/onnxruntime/python/tools/quantization/quant_utils.py
+++ b/onnxruntime/python/tools/quantization/quant_utils.py
@@ -671,21 +671,41 @@ def write_calibration_table(calibration_cache, dir="."):
     import json
 
     import flatbuffers
+    import numpy as np
 
     import onnxruntime.quantization.CalTableFlatBuffers.KeyValue as KeyValue
     import onnxruntime.quantization.CalTableFlatBuffers.TrtTable as TrtTable
+    from onnxruntime.quantization.calibrate import CalibrationMethod, TensorData, TensorsData
 
     logging.info(f"calibration cache: {calibration_cache}")
 
+    class MyEncoder(json.JSONEncoder):
+        def default(self, obj):
+            if isinstance(obj, (TensorData, TensorsData)):
+                return obj.to_dict()
+            if isinstance(obj, np.ndarray):
+                return {"data": obj.tolist(), "dtype": str(obj.dtype), "CLS": "numpy.array"}
+            if isinstance(obj, CalibrationMethod):
+                return {"CLS": obj.__class__.__name__, "value": str(obj)}
+            return json.JSONEncoder.default(self, obj)
+
+    json_data = json.dumps(calibration_cache, cls=MyEncoder)
+
     with open(os.path.join(dir, "calibration.json"), "w") as file:
-        file.write(json.dumps(calibration_cache))  # use `json.loads` to do the reverse
+        file.write(json_data)  # use `json.loads` to do the reverse
 
     # Serialize data using FlatBuffers
+    zero = np.array(0)
     builder = flatbuffers.Builder(1024)
     key_value_list = []
     for key in sorted(calibration_cache.keys()):
         values = calibration_cache[key]
-        value = str(max(abs(values[0]), abs(values[1])))
+        d_values = values.to_dict()
+        floats = [
+            float(d_values.get("highest", zero).item()),
+            float(d_values.get("lowest", zero).item()),
+        ]
+        value = str(max(floats))
 
         flat_key = builder.CreateString(key)
         flat_value = builder.CreateString(value)
@@ -724,9 +744,14 @@ def write_calibration_table(calibration_cache, dir="."):
     # write plain text
     with open(os.path.join(dir, "calibration.cache"), "w") as file:
         for key in sorted(calibration_cache.keys()):
-            value = calibration_cache[key]
-            s = key + " " + str(max(abs(value[0]), abs(value[1])))
-            file.write(s)
+            values = calibration_cache[key]
+            d_values = values.to_dict()
+            floats = [
+                float(d_values.get("highest", zero).item()),
+                float(d_values.get("lowest", zero).item()),
+            ]
+            value = key + " " + str(max(floats))
+            file.write(value)
             file.write("\n")
 
 
diff --git a/onnxruntime/test/python/quantization/test_qdq.py b/onnxruntime/test/python/quantization/test_qdq.py
index d3718de1aa56a..b99c11abf6d2c 100644
--- a/onnxruntime/test/python/quantization/test_qdq.py
+++ b/onnxruntime/test/python/quantization/test_qdq.py
@@ -22,8 +22,8 @@
     create_clip_node,
 )
 
-from onnxruntime.quantization import QDQQuantizer, QuantFormat, QuantType, quantize_static
-from onnxruntime.quantization.calibrate import TensorData
+from onnxruntime.quantization import QDQQuantizer, QuantFormat, QuantType, quantize_static, write_calibration_table
+from onnxruntime.quantization.calibrate import CalibrationMethod, TensorData, TensorsData
 
 
 class TestQDQFormat(unittest.TestCase):
@@ -1720,6 +1720,11 @@ def test_int4_qdq_per_channel_conv(self):
         size_ratio = weight_quant_init.ByteSize() / unpacked_size
         self.assertLess(size_ratio, 0.55)
 
+    def test_json_serialization(self):
+        td = TensorData(lowest=np.array([0.1], dtype=np.float32), highest=np.array([1.1], dtype=np.float32))
+        new_calibrate_tensors_range = TensorsData(CalibrationMethod.MinMax, {"td": td})
+        write_calibration_table(new_calibrate_tensors_range)
+
 
 if __name__ == "__main__":
     unittest.main()