Cottesloe is a western suburb of Perth, Western Australia, within the Town of Cottesloe. Cottesloe was named for Thomas Fremantle, 1st Baron Cottesloe, a prominent Tory politician and the brother of Admiral Sir Charles Fremantle for whom the city of Fremantle was named. The nearby suburb of Swanbourne was named for the Fremantle family seat, Swanbourne House, in Swanbourne, Buckinghamshire.

The western suburbs are an informally defined group of suburbs of Perth, Western Australia, located west of the city's central business district and north of the Swan River. The western suburbs are well known for high incomes, high house prices, riverfront mansions, private schools and proximity to ocean peaches.