diff --git a/packages/google-cloud-storage/google/cloud/storage/_media/_download.py b/packages/google-cloud-storage/google/cloud/storage/_media/_download.py
index 593a152c0a17..eea0eaf708db 100644
--- a/packages/google-cloud-storage/google/cloud/storage/_media/_download.py
+++ b/packages/google-cloud-storage/google/cloud/storage/_media/_download.py
@@ -66,6 +66,8 @@ def __init__(
         end=None,
         headers=None,
         retry=DEFAULT_RETRY,
+        client_info_bucket_name=None,
+        client_info_object_name=None,
     ):
         self.media_url = media_url
         self._stream = stream
@@ -76,6 +78,8 @@ def __init__(
         self._headers = headers
         self._finished = False
         self._retry_strategy = retry
+        self.client_info_bucket_name = client_info_bucket_name
+        self.client_info_object_name = client_info_object_name
 
     @property
     def finished(self):
@@ -487,6 +491,35 @@ def _process_response(self, response):
         # Write the response body to the stream.
         self._stream.write(response_body)
 
+        if self._finished:
+            requested_length = None
+            if self.start is not None and self.start < 0 and self.end is None:
+                requested_length = -self.start
+            elif self.start is not None and self.end is not None:
+                requested_length = self.end - self.start + 1
+            elif self.start is None and self.end is not None:
+                requested_length = self.end + 1
+
+            if (
+                requested_length is not None
+                and self._bytes_downloaded > requested_length
+            ):
+                if response.headers.get("x-goog-stored-content-encoding") != "gzip":
+                    import logging
+
+                    logger = logging.getLogger(__name__)
+                    bucket_name = (
+                        getattr(self, "client_info_bucket_name", None) or "unknown"
+                    )
+                    object_name = (
+                        getattr(self, "client_info_object_name", None) or "unknown"
+                    )
+                    diff = self._bytes_downloaded - requested_length
+                    logger.warning(
+                        f"storage: received {diff} more bytes than requested from GCS "
+                        f'for bucket "{bucket_name}", object "{object_name}"'
+                    )
+
     def consume_next_chunk(self, transport, timeout=None):
         """Consume the next chunk of the resource to be downloaded.
 
diff --git a/packages/google-cloud-storage/google/cloud/storage/blob.py b/packages/google-cloud-storage/google/cloud/storage/blob.py
index 87d97ef739cd..44573209e813 100644
--- a/packages/google-cloud-storage/google/cloud/storage/blob.py
+++ b/packages/google-cloud-storage/google/cloud/storage/blob.py
@@ -1120,8 +1120,35 @@ def _do_download(
                 attributes=extra_attributes,
                 api_request=args,
             ):
+                response = None
                 while not download.finished:
-                    download.consume_next_chunk(transport, timeout=timeout)
+                    response = download.consume_next_chunk(transport, timeout=timeout)
+
+        requested_length = None
+        if start is not None and start < 0 and end is None:
+            requested_length = -start
+        elif start is not None and end is not None:
+            requested_length = end - start + 1
+        elif start is None and end is not None:
+            requested_length = end + 1
+
+        if requested_length is not None and requested_length >= 0:
+            received_bytes = getattr(download, "_bytes_downloaded", 0)
+            if isinstance(received_bytes, int) and received_bytes > requested_length:
+                from google.cloud.storage._media import _helpers as media_helpers
+
+                if (
+                    response is not None
+                    and not media_helpers._is_decompressive_transcoding(
+                        response, download._get_headers
+                    )
+                ):
+                    _logger.warning(
+                        "storage: received %d more bytes than requested from GCS for bucket %r, object %r",
+                        received_bytes - requested_length,
+                        self.bucket.name,
+                        self.name,
+                    )
 
     def download_to_file(
         self,
diff --git a/packages/google-cloud-storage/tests/unit/test_blob.py b/packages/google-cloud-storage/tests/unit/test_blob.py
index 0d2f11339628..bf0ed876f563 100644
--- a/packages/google-cloud-storage/tests/unit/test_blob.py
+++ b/packages/google-cloud-storage/tests/unit/test_blob.py
@@ -1374,6 +1374,45 @@ def test__do_download_wo_chunks_w_range_w_raw_w_headers(self):
             w_range=True, raw_download=True, headers={"If-Match": "kittens"}
         )
 
+    @mock.patch("google.cloud.storage.blob._logger")
+    def test__do_download_log_extra_bytes(self, mock_logger):
+        blob_name = "blob-name"
+        client = self._make_client()
+        bucket = _Bucket(client)
+        blob = self._make_one(blob_name, bucket=bucket)
+        blob.chunk_size = None
+
+        transport = object()
+        file_obj = io.BytesIO()
+        download_url = "http://test.invalid"
+
+        patch = mock.patch("google.cloud.storage.blob.Download")
+        with patch as patched:
+            download = patched.return_value
+            download._bytes_downloaded = 10
+            type(download).finished = mock.PropertyMock(side_effect=[False, True])
+
+            mock_response = mock.Mock()
+            mock_response.headers = {}
+            download.consume_next_chunk.return_value = mock_response
+            download._get_headers.return_value = {}
+
+            blob._do_download(
+                transport,
+                file_obj,
+                download_url,
+                {},
+                start=0,
+                end=4,
+            )
+
+        mock_logger.warning.assert_called_once_with(
+            "storage: received %d more bytes than requested from GCS for bucket %r, object %r",
+            5,
+            "name",
+            "blob-name",
+        )
+
     def test__do_download_wo_chunks_w_custom_timeout(self):
         self._do_download_helper_wo_chunks(
             w_range=False, raw_download=False, timeout=9.58