William Oats (27 October 1841 – 25 April 1911) was an Australian mining engineer and politician who served in both houses of the Parliament of Western Australia, as a member of the Legislative Assembly from 1897 to 1904 and a member of the Legislative Council from 1904 to 1910.

He went to New South Wales the following year, where he was in charge of a tin mine at Eurowrie (in the Barrier Ranges).

Oats came to Western Australia in 1888, having accepted the position of manager at a gold mine in Southern Cross.

He was subsequently responsible for making it into one of the first profitable gold mines in Western Australia.

He served a single six-year term before retiring due to ill health, and died in Perth in 1911, aged 69.