The rhinoceros ratsnake, also known commonly as the rhinoceros snake, rhino rat snake, and Vietnamese longnose snake, is a species of nonvenomous ratsnake in the family Colubridae. The species is found from northern Vietnam to southern China. It has a prominent, distinctive, scaled protrusion on the front of its snout, which has led to its common naming after a rhinoceros.

Rat snakes are members – along with kingsnakes, milk snakes, vine snakes and indigo snakes – of the subfamily Colubrinae of the family Colubridae. They are medium to large constrictors and are found throughout much of the Northern Hemisphere. They feed primarily on rodents. Many species make attractive and docile pets and one, the corn snake, is one of the most popular reptile pets in the world. Like all snakes, they can be defensive when approached too closely, handled, or restrained. However, rat snake bites are not dangerous to humans. Like nearly all colubrids, rat snakes pose no threat to humans. Rat snakes were long believed to be completely nonvenomous, but recent studies have shown that some Old World species do possess small amounts of venom, though the amount is negligible relative to humans.