Pamphobeteus is a genus of tarantulas (family Theraphosidae) native to northwestern South America: Colombia, Ecuador, Peru, Bolivia and Brazil. It includes some of the largest spiders in the world. Pamphobeteus was first believed to be a member of the Lasidora genus, but was later distinguished by the lack of scopulae on the inferior side of the first leg femur and the differences in the organ for stridulation.