Cayman Brac is an island that is part of the Cayman Islands. It lies in the Caribbean Sea about 145 km (90 mi) north-east of Grand Cayman and 8 km (5.0 mi) east of Little Cayman. It is about 19 km (12 mi) long, with an average width of 2 km (1.2 mi). Its terrain is the most prominent of the three Cayman Islands due to "The Bluff", a limestone outcrop that rises steadily along the length of the island up to 43 m (141 ft) above sea level at the eastern end. The island is named after this prominent feature, as "brac" is a Gaelic name for a bluff.

The Teignmouth Electron, the boat in which Donald Crowhurst attempted to sail round the world single-handed in the Sunday Times Golden Globe Race, has been left to decay on the south coast of Cayman Brac.