Lassie is a Rough Collie. This breed is known for its long, luxurious coat, intelligence, loyalty, and herding abilities. Despite being a female character, all dogs that played Lassie in films and TV shows were male Rough Collies. The breed is medium to large-sized and originally comes from Scotland where it was used to herd sheep. Lassies are famous for their courage, intelligence, and devotion, traits well exemplified by the Rough Collie breed.