diff --git a/S3/S3.py b/S3/S3.py
index ec90a775..d95c3ba8 100644
--- a/S3/S3.py
+++ b/S3/S3.py
@@ -11,6 +11,7 @@
 ## --------------------------------------------------------------------
 
 from __future__ import absolute_import, division
+import base64
 
 import sys
 import os
@@ -1725,6 +1726,10 @@ def send_file(self, request, stream, labels, buffer = '', throttle = 0,
             sha256_hash = checksum_sha256_file(stream, offset, size_total)
         request.body = sha256_hash
 
+        # Provide the checksum with teh request. This is important for buckets that have 
+        # Object Lock enabled.
+        headers['x-amz-checksum-sha256'] = base64.b64encode(sha256_hash.digest()).decode()
+
         if use_expect_continue:
             if not size_total:
                 use_expect_continue = False