The Staffordshire Bull Terrier, also called the Staffy or Stafford, is a purebred dog of small to medium size in the terrier group that originated in the northern parts of Birmingham and in the Black Country of Staffordshire, for which it is named. They descended from 19th-century bull terriers that were developed by crossing bulldogs with various terriers to create a generic type of dog generally known as bull and terriers. Staffords share the same ancestry with the modern Bull Terrier, although the two breeds developed along independent lines, and do not resemble each other. Modern Staffords more closely resemble the old type of bull terrier, and were first recognised as a purebred dog breed by The Kennel Club of Great Britain in 1935.

Watchman, a Staffordshire Bull Terrier, is a military mascot of the now disbanded Staffordshire Regiment. He continues his duties as part of the Staffordshire Regimental Association. The same name has been given to a succession of Staffordshire Bull Terriers – as of 2018, six.