diff --git a/moto/s3/responses.py b/moto/s3/responses.py
index fbd142a34..86d5dbdef 100755
--- a/moto/s3/responses.py
+++ b/moto/s3/responses.py
@@ -636,6 +636,8 @@ class ResponseObject(_TemplateEnvironmentMixin):
 
         storage_class = request.headers.get('x-amz-storage-class', 'STANDARD')
         acl = self._acl_from_headers(request.headers)
+        if acl is None:
+            acl = self.backend.get_bucket(bucket_name).acl
         tagging = self._tagging_from_headers(request.headers)
 
         if 'acl' in query:
@@ -740,7 +742,7 @@ class ResponseObject(_TemplateEnvironmentMixin):
         if grants:
             return FakeAcl(grants)
         else:
-            return get_canned_acl('private')
+            return None
 
     def _tagging_from_headers(self, headers):
         if headers.get('x-amz-tagging'):
diff --git a/tests/test_s3/test_s3.py b/tests/test_s3/test_s3.py
index 4fc698787..8ce56bd01 100644
--- a/tests/test_s3/test_s3.py
+++ b/tests/test_s3/test_s3.py
@@ -870,7 +870,7 @@ def test_s3_object_in_public_bucket():
     s3 = boto3.resource('s3')
     bucket = s3.Bucket('test-bucket')
     bucket.create(ACL='public-read')
-    bucket.put_object(ACL='public-read', Body=b'ABCD', Key='file.txt')
+    bucket.put_object(Body=b'ABCD', Key='file.txt')
 
     s3_anonymous = boto3.resource('s3')
     s3_anonymous.meta.client.meta.events.register('choose-signer.s3.*', disable_signing)