The chestnut-backed buttonquail (Turnix castanotus) is a species of bird in the family Turnicidae. It is endemic to Australia.
Native to northern Australia, the species ranges from the Dampier Peninsula in Western Australia across to Westmoreland Station in the Gulf Country of northwestern Queensland, with possible records from Gregory Downs and Augustus Downs further east. It is also native to Melville Island and Groote Eylandt. It was common around Borroloola and McArthur River, but not currently. Its existence in Queensland was only confirmed in 2020.
The usual sex roles are reversed in the buttonquail genus (Turnix), as the larger and more brightly-coloured female mates with multiple male partners and leaves them to incubate the eggs. The female lays a clutch of 1–5 (usually 4) pyriform eggs, which are glossy-white with sparse small dark blotches.