This article is about the non-vascular plants. The name Hornwort also refers to aquatic plants of the genus Ceratophyllum, in the family Ceratophyllaceae.

Hornworts are a group of bryophytes, or non-vascular plants, comprising the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. The flattened, green plant body of a hornwort is the gametophyte plant.