Ferntree Gully is a suburb in Melbourne, Victoria, Australia, at the foothills of the Dandenong Ranges, 27 km east of Melbourne's Central Business District, located within the City of Knox local government area. Ferntree Gully recorded a population of 27,398 at the 2021 census.

The Dandenong Ranges are a set of low mountain ranges in Victoria, Australia, approximately 35 km (22 mi) east of the state capital Melbourne. A minor branch of the Great Dividing Range, the Dandenongs consist mostly of rolling hills, rising to 633 m (2,077 ft) at Mount Dandenong, as well as steeply weathered valleys and gullies covered in thick temperate rainforest, predominantly of tall mountain ash trees and dense ferny undergrowth. The namesaked Dandenong Creek and most of its left-bank tributaries originate from headwaters in these mountain ranges. Two of Melbourne's most important storage reservoirs, the Cardinia and Silvan Reservoir, are also located within the Dandenongs.