diff --git a/requirements-opt.txt b/requirements-opt.txt
index 101e7d7b..a4d25a67 100644
--- a/requirements-opt.txt
+++ b/requirements-opt.txt
@@ -1 +1,3 @@
 tqdm==4.65.0
+fsspec==2023.10.0
+s3fs==2023.10.0
diff --git a/setup.py b/setup.py
index 4ff0eb53..a4f1c0e9 100755
--- a/setup.py
+++ b/setup.py
@@ -41,7 +41,9 @@
     'url': 'https://github.com/hdmf-dev/hdmf-zarr',
     'license': "BSD",
     'install_requires': reqs,
-    'extras_require': {"tqdm": ["tqdm>=4.41.0"]},
+    'extras_require': {"tqdm": ["tqdm>=4.41.0"],
+                       "fsspec": ["fsspec"],
+                       "s3fs": ["s3fs"]},
     'packages': pkgs,
     'package_dir': {'': 'src'},
     'package_data': {},