diff --git a/google/cloud/storage/transfer_manager.py b/google/cloud/storage/transfer_manager.py
index fafe68f1c..a34419020 100644
--- a/google/cloud/storage/transfer_manager.py
+++ b/google/cloud/storage/transfer_manager.py
@@ -1136,7 +1136,7 @@ def upload_chunks_concurrently(
                     end=end,
                     part_number=part_number,
                     checksum=checksum,
-                    headers=headers,
+                    headers=headers.copy(),
                     retry=retry,
                 )
             )