diff --git a/storages/backends/s3boto3.py b/storages/backends/s3boto3.py
index 727782f76..212179004 100644
--- a/storages/backends/s3boto3.py
+++ b/storages/backends/s3boto3.py
@@ -387,6 +387,7 @@ def _decode_name(self, name):
 
     def _compress_content(self, content):
         """Gzip a given string content."""
+        content.seek(0)
         zbuf = BytesIO()
         zfile = GzipFile(mode='wb', compresslevel=6, fileobj=zbuf)
         try: