The Cape Breton accent is a variety of Canadian English spoken on Cape Breton Island off the eastern coast of the province of Nova Scotia in Canada. Most of the inhabitants of European ancestry descend from people long resident on the island, and the community has had time to develop a local dialect. Much of the population is descended from Highland Scottish settlers fleeing the Highland Clearances. But there has long been a French Acadian element on the island, as well as some Irish.

The primary influences on the accent are Scottish Gaelic and Scots. Other Celtic languages and Acadian French have been influential as well. The rhythm of speech is generally quick-paced, with unstressed syllables often completely elided.

One feature of Cape Breton dialect is common use of the term 'boy', often given the spelling "b'y" and pronounced "bye" as in 'good-bye', to address a person to whom one is speaking in lieu of use of the person's name or a more common term such as 'sir', 'man', or 'mate', particularly when the addressee is male. A plural form "b'ys" is used to address male addressees. The terms can also be used to refer to a person or people not being addressed. This feature of Cape Breton vernacular is also characteristic of Newfoundland English.