Kalgoorlie is a city in the Goldfields–Esperance region of Western Australia, located 595 km (370 mi) east-northeast of Perth at the end of the Great Eastern Highway. It is sometimes referred to as Kalgoorlie–Boulder, as the surrounding urban area includes the historic townsite of Boulder and the local government area is the City of Kalgoorlie–Boulder.

Kalgoorlie-Boulder lies on the traditional lands of the Wangkatja group of peoples.The name "Kalgoorlie" is derived from the Wangai word Karlkurla or Kulgooluh, meaning "place of the silky pears". The city was established in 1893 during the Western Australian gold rushes. It soon replaced Coolgardie as the largest settlement on the Eastern Goldfields. Kalgoorlie is the ultimate destination of the Goldfields Water Supply Scheme and the Golden Pipeline Heritage Trail. The nearby Super Pit gold mine was Australia's largest open-cut gold mine for many years.

At June 2018, Kalgoorlie–Boulder had an estimated urban population of 29,849, a decline from the recent peak of 32,966 in 2013.