Underdale is a western suburb of South Australia's capital city Adelaide on Kaurna land.

It is largely residential with a very small industrial section on the eastern side of Holbrook's Road near the river.

Underdale High School sits within the suburb; its alumni include cricket player David Hookes[2] and Australian soccer player Tony Vidmar.

Australian Bureau of Statistics data from May 2021 identified Adelaide's western suburbs as having the lowest unemployment rate in South Australia.

Underdale Post Office first opened on 1 January 1867 and closed around 1874.