Wallaroo is a port town on the western side of Yorke Peninsula in South Australia, 160 kilometres north-northwest of Adelaide. It is one of the three Copper Triangle towns famed for their historic shared copper mining industry, and known together as "Little Cornwall", the other two being Kadina (about 8 kilometres to the east) and Moonta (about 18 kilometres south). At the 2006 census, Wallaroo had a population of 3,053.
The name "Wallaroo" comes from the Aboriginal word wadlu waru, meaning wallaby urine. The early settlers tried to copy the aboriginals by calling it Walla Waroo. However, they found this too big to stamp on the wool bales, so they shortened it to Wallaroo.
Since 1999, the rural broadacre farming area to the north of the town has been officially known as Wallaroo Plain The area south of Wallaroo is Warburto. The Warburto railway station name was derived from the Narungga name for a nearby spring.