The Erycinae, also known as the Old World sand boas, are a subfamily of nonvenomous snakes in the family Boidae. Species of the subfamily Erycinae are found in Europe, Asia Minor, Africa, Arabia, central and southwestern Asia, India, Sri Lanka, and western North America. Four genera comprising 18 species are currently recognized as being valid.

The Boidae, commonly known as boas or boids, are a family of nonvenomous snakes primarily found in the Americas, as well as Africa, Europe, Asia, and some Pacific islands. Boas include some of the world's largest snakes, with the green anaconda of South America being the heaviest and second-longest snake known; in general, adults are medium to large in size, with females usually larger than the males. Six subfamilies comprising 15 genera and 54 species are currently recognized.