Brachypelma smithi is a species of spider in the family Theraphosidae (tarantulas) native to Mexico. It has been confused with Brachypelma hamorii; both have been called Mexican redknee tarantulas. Mexican redknee tarantulas are a popular choice as pets among tarantula keepers. Many earlier sources referring to B. smithi either relate to B. hamorii or do not distinguish between the two species. B. smithi is a terrestrial tarantula native to Pacific coast of the Mexican state of Guerrero.

Brachypelma hamorii is a vulnerable species of tarantula found in Mexico. It has been confused with B. smithi; both have been called Mexican redknee tarantulas. Many earlier sources referring to B. smithi either do not distinguish between the two species or relate to B. hamorii. B. hamorii is a terrestrial tarantula native to the western faces of the Sierra Madre Occidental and Sierra Madre del Sur mountain ranges in the Mexican states of Colima, Jalisco, and Michoacán. The species is a large spider, adult females having a total body length over 50 mm (2 in) and males having legs up to 75 mm (3 in) long. Mexican redknee tarantulas are a popular choice for enthusiasts. Like most tarantulas, it has a long lifespan.