Tantilla is a large genus of harmless New World snakes in the family Colubridae. The genus includes 66 species, which are commonly known as centipede snakes, black-headed snakes, and flathead snakes.

Colubridae is a family of snakes. With 249 genera, it is the largest snake family. The earliest fossil species of the family date back to the Late Eocene epoch, with earlier origins suspected. Colubrid snakes are found on every continent except Antarctica.