diff --git a/requirements-doc.txt b/requirements-doc.txt
index 2050f4439..c37aee646 100644
--- a/requirements-doc.txt
+++ b/requirements-doc.txt
@@ -12,3 +12,4 @@ dataframe_image   # used to render large dataframe as image in the sphinx galler
 lxml  # used by dataframe_image when using the matplotlib backend
 hdf5plugin
 dandi>=0.46.6
+hdmf-zarr