鞘嘴鸥科（学名：Chionididae）是鸻形目的一个单型科，目前仅存两种：白鞘嘴鸥（C. alba）和黑脸鞘嘴鸥（C. minor），全部分布于南极洲。通体白色，其上喙覆盖有角质薄膜，故名。杂食性，常以海藻、鸟粪、鸟蛋、幼鸟、死尸等为食。

The sheathbills are a family of birds, Chionididae. Classified in the wader order Charadriiformes, the family contains one genus, Chionis, with only two species. They breed on subantarctic islands and the Antarctic Peninsula, and the snowy sheathbill migrates to the Falkland Islands and coastal southern South America in the southern winter; they are the only bird family endemic as breeders to the Antarctic region. They are also the only Antarctic birds without webbed feet.