Tandayarachne is a genus of spiders in the family Theraphosidae.
Tandayarachne is found in Colombia and Ecuador.
The genus name is a combination of Tandayapa Cloud Forest Station, the type location in the Alambi river basin in Pichincha Province, Ecuador, and Ancient Greek arachne "spider". T. sherwoodae honors UK arachnologist .
, this genus includes two species: