Bras d'Or Lake (Mi'kmawi'simk: Pitupaq) is an irregular estuary in the centre of Cape Breton Island in Nova Scotia, Canada.

[8] An error of folk etymology, the name is spelt to resemble the French language Arm of Gold, a homonym.

[15] The southern tip of the lake is connected to the Atlantic Ocean via the St. Peters Canal, built for shipping traffic in the 1860s.

Fish species include the blackspotted stickleback, white hake, blueback herring, Greenland cod, and introduced rainbow trout.

[16]: 23 [17][18] Mi'kmaq peoples occupied lands around Bras d'Or Lake when European explorers first arrived.

Named Unama'ki in their language, it is the fire (or capital district) of their country, Mi'kma'ki, part of the greater Wabanaki Confederacy of the Dawnland region.

[9] Alexander Graham Bell built an estate Beinn Bhreagh where he established a research laboratory, and used the lake to test man-carrying kites, airplanes and hydrofoil boats.