A genus of ringworm fungi of the family Moniliaceae: In the genus Trichophyton there are hyaline single-celled spores which are parasitic in the skin and hair follicles of humans and lower mammals.

Trichophyton includes parasitic fungi that live in or on the skin or its appendages (hair and nails) and are the cause of various dermatomycoses and ringworm infections.

Species that produce spores arranged in rows on the outside of the hair are designated "ectothrix", and if the spores are within the hair, they are termed "endothrix".