Euathlus affinis is a species of spider belonging to the family Theraphosidae (tarantulas).

[1] The species was first described in 1849 as Mygale affinis.

However, Mygale had been used previously for a genus of mammals, and the correct name for the genus is Avicularia,[2] making this species Avicularia affinis.

It was subsequently transferred to Brachypelma in 1936 and then to Euathlus in 2017.

[1] This Theraphosidae-related article is a stub.