Undercliffe is an area in the east of the suburb of Earlwood in south-western Sydney, in the state of New South Wales, Australia. Undercliffe is located 10 kilometres south-west of the Sydney central business district in the local government area of the Canterbury-Bankstown Council.
Undercliffe was a suburb of Sydney until incorporation into Earlwood in 1993.
Undercliffe is located on the peninsula between the Cooks River and Wolli Creek. Bayview Avenue and Unwins Bridge link Undercliffe north over the Cooks River to Tempe. Another bridge links Illawarra Avenue over the Cooks River to Marrickville. Wolli Creek and Turrella are located on the opposite bank of Wolli Creek, to the south, with footbridges being the only direct links to these suburbs.