Peppermint Grove is an affluent western suburb of Perth, Western Australia on the north bank of the Swan River at Freshwater Bay. Its local government area, the smallest in the country, is the Shire of Peppermint Grove. The suburb was named after the Swan River peppermint trees lining many streets. The suburb has long been associated with Western Australia's wealthiest and oldest families. Their prosperity is reflected in the many historical houses in the area, such as The Cliffe and the Federation Queen Anne style St Just. Colin Barnett, a former Premier of Western Australia, dubbed the suburb "Monaco of WA" due to its small size and concentration of wealth. It is also known as millionaire’s row and had the highest income of any suburb in Australia in 2022.

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.