The Collie is a distinctive type of herding dog, including many related landraces and formal breeds. It originates in Scotland and Northern England. It is a medium-sized, fairly lightly built dog with a pointed snout, and many types have a distinctive white pattern over the shoulders. Collies are very active and agile, and most types have a very strong herding instinct. The collie type has spread through many parts of the world (especially Australia and North America) and has diversified into many varieties, sometimes with mixture from other dog types. Some of the collie types have remained as working dogs, used for herding cattle, sheep and other livestock, while others are kept as pets, show dogs or for dog sports, in which they display great agility, stamina and trainability. While the AKC does have a breed they call "Collie", the truth in fact is that collie dogs are a distinctive type of herding dog including many related landraces and formal breeds. It is thought to originate in the region surrounding Scotland and Northern England. They have spread throughout the world (especially Australia, North America and South America) and diversified into many breed types. Some collies are still used for herding or farm dogs, while others have been bred for companionship. There is usually major distinctions between show dogs and those bred for herding trials or dog sports. They typically display great agility, stamina and trainability and more importantly sagacity.

Common use of the name "collie" in some areas is limited largely to certain breeds – such as to the Rough Collie in parts of the United States, or to the Border Collie in many rural parts of Great Britain. Many collie types do not actually include "collie" in their name.