Pit bull is a term commonly used to describe several breeds of dog in the Molosser family. The term can also refer to dogs that were known as “bull terriers” prior to the development of the modern Bull Terrier in the early 20th century.

Many breed-specific laws use the term “pit bull” to refer to the modern American Pit Bull Terrier, American Staffordshire Terrier, and Staffordshire Bull Terrier, and dogs with significant mixes of these breeds; however, a few jurisdictions also classify the modern American Bulldog and Bull Terrier as a “pit bull-type dog”.

The history of the pit bull-type dog reflects the history of its constituent breeds: the American Pit Bull Terrier, the American Staffordshire Terrier, and the Staffordshire Bull Terrier.