The Rough Collie (also known as the Long-Haired Collie) is a long-coated dog breed of medium to large size that, in its original form, was a type of collie used and bred for herding sheep in Scotland. More recent breeding has focused on the Collie as a show dog, and also companion. The breed specifications call for a distinctive long narrow tapered snout and tipped (semiprick) ears, so some dogs have their ears taped when young. Rough Collies generally come in shades of sable and white (sometimes mahogany), blue merle, tri-colored, and colour-headed white.

Originating in the 19th century, the breed is now well known through the stories of author Albert Payson Terhune about his dog Lad, and later with Eric Knight's character of Lassie and her novels, movies, and television shows.

There is a smooth-coated variety known as a Smooth Collie; some breed organisations, including both the American and Canadian Kennel Clubs, consider smooth-coat and rough-coat collies to be variations of the same breed. Rough Collies closely resemble the smaller Shetland Sheepdogs or "Shelties", but the two breeds do not have an exclusive linear relationship.