Euathlus is a genus of South American tarantulas that was first described by Anton Ausserer in 1875. These spiders are medium sized and are usually found in high elevations in the Andes. It is a senior synonym of Paraphysa, and was formerly considered a senior synonym of Brachypelma, but this was later rejected.

Tarantulas comprise a group of large and often hairy spiders of the family Theraphosidae. As of December 2023, 1,100 species have been identified, with 166 genera. The term "tarantula" is usually used to describe members of the family Theraphosidae, although many other members of the same infraorder (Mygalomorphae) are commonly referred to as "tarantulas" or "false tarantulas". Some of the more common species have become popular in the exotic pet trade. Many New World species kept as pets have setae known as urticating hairs that can cause irritation to the skin, and in extreme cases, cause damage to the eyes.