diff --git a/gallery_dl/option.py b/gallery_dl/option.py
index 4d5e463a..4d9a3587 100644
--- a/gallery_dl/option.py
+++ b/gallery_dl/option.py
@@ -267,6 +267,11 @@ def build_parser():
         dest="filesize-max", metavar="SIZE", action=ConfigAction,
         help="Do not download files larger than SIZE (e.g. 500k or 2.5M)",
     )
+    downloader.add_argument(
+        "--chunk-size",
+        dest="chunk-size", metavar="SIZE", action=ConfigAction,
+        help="Size of in-memory data chunks (default: 32k)",
+    )
     downloader.add_argument(
         "--no-part",
         dest="part", nargs=0, action=ConfigConstAction, const=False,