West Highland White Terriers, commonly known as Westies, are a breed of dog known for their spirited personality and brilliant white coat. They are friendly, good with children, and thrive on lots of attention. Like most terriers, they have plenty of attitude (some might say "spirit") for a dog their size. This breed is commonly recognized because it is used as a mascot for Black & White (a brand of Scotch whisky) and for Cesar brand dog food.

Westies are descended from Cairn Terriers, who occasionally whelped white puppies naturally, and Scottish Terriers; who also occasionally produced white offspring. White offspring from other British Terriers such as the Bedlington Terrier and Dandie Dinmont Terrier were occasionally introduced to the bloodline for desired characteristics, but this practice generally stopped in the 1850s.

Some sources credit Colonel Edward Donald Malcolm and his kin of Poltalloch, in the Argyll region of Western Scotland as an originator of this breed in the 1800s. Other sources credit the 8th Duke of Argyll (Chieftan of Clan Campbell) as an originator of the breed. However, there may have been some cooperation between the two gentlemen. It may have taken as long as a hundred years of selective breeding to produce all the desired qualities. Their white coat made them highly visible when hunting on the Scottish moors and easily distinguished them from their game. They also possess a sturdy frame.

Originally the breed was known as Poltalloch Terriers (after the name of Malcolm's home), although they were also known as Roseneath Terriers (after the name of Argyll's home), White Roseneath Terriers, and at the end of the 19th century, briefly as a white variety of the Scottish Terrier.