diff --git a/AUTHORS.rst b/AUTHORS.rst
index 3aa2a1e5..1dbd0409 100644
--- a/AUTHORS.rst
+++ b/AUTHORS.rst
@@ -173,3 +173,4 @@ Patches and Suggestions
 - Om Prakash Kumar <omprakash070@gmail.com> (`@iamprakashom <https://github.com/iamprakashom>`_)
 - Philipp Konrad <gardiac2002@gmail.com> (`@gardiac2002 <https://github.com/gardiac2002>`_)
 - Hussain Tamboli <hussaintamboli18@gmail.com> (`@hussaintamboli <https://github.com/hussaintamboli>`_)
+- Casey Davidson (`@davidsoncasey <https://github.com/davidsoncasey>`_)
diff --git a/tests/test_requests.py b/tests/test_requests.py
index 2c298bab..49417717 100755
--- a/tests/test_requests.py
+++ b/tests/test_requests.py
@@ -1693,6 +1693,42 @@ class TestRequests:
         resp.close()
         assert resp.raw.closed
 
+    def test_empty_stream_with_auth_does_not_set_content_length_header(self, httpbin):
+        """Ensure that a byte stream with size 0 will not set both a Content-Length
+        and Transfer-Encoding header.
+        """
+        auth = ('user', 'pass')
+        url = httpbin('post')
+        file_obj = io.BytesIO(b'')
+        r = requests.Request('POST', url, auth=auth, data=file_obj)
+        prepared_request = r.prepare()
+        assert 'Transfer-Encoding' in prepared_request.headers
+        assert 'Content-Length' not in prepared_request.headers
+
+    def test_stream_with_auth_does_not_set_transfer_encoding_header(self, httpbin):
+        """Ensure that a byte stream with size > 0 will not set both a Content-Length
+        and Transfer-Encoding header.
+        """
+        auth = ('user', 'pass')
+        url = httpbin('post')
+        file_obj = io.BytesIO(b'test data')
+        r = requests.Request('POST', url, auth=auth, data=file_obj)
+        prepared_request = r.prepare()
+        assert 'Transfer-Encoding' not in prepared_request.headers
+        assert 'Content-Length' in prepared_request.headers
+
+    def test_chunked_upload_does_not_set_content_length_header(self, httpbin):
+        """Ensure that requests with a generator body stream using
+        Transfer-Encoding: chunked, not a Content-Length header.
+        """
+        data = (i for i in [b'a', b'b', b'c'])
+        url = httpbin('post')
+        r = requests.Request('POST', url, data=data)
+        prepared_request = r.prepare()
+        assert 'Transfer-Encoding' in prepared_request.headers
+        assert 'Content-Length' not in prepared_request.headers
+
+
 class TestCaseInsensitiveDict:
 
     @pytest.mark.parametrize(