Edgar Alfred "Oscar" Oates (1 Nov 1889 – 2 September 1951) was a politician in the State of South Australia.
He was born at Kangaroo Flat, 5 km north of Gawler, and worked as a wharf labourer at Port Adelaide. He was a member of the Waterside Workers Federation from 1916 to the day he died.
He was president of the SA Public Schools Committees' Association.
He was elected for Labor in 1933 to the Legislative Council for the Central No. 1 district, with a substantial support from preferences.
During his term of office he made three attempts to introduce a State lottery, and was about to make a fourth on the week he died. He also made considerable attempts to have a new hospital built in the Port Adelaide area. He was a member of the Parliamentary Land Settlement Committee, and Libraries and Printing Committees.
He was married to Ada Grace; they had a son, Alfred J. G. Oates of Rosewater and a daughter Joan, Mrs. A McDonald of Rosewater Gardens. They lived at 38 Junction road. Rosewater.