William O'Brien (Australian politician)

William Joseph O'Brien (7 September 1882 – 15 June 1953) was an Australian politician.

He was born in Parkes to carrier William O'Brien and Bridget, née O'Sullivan.

He worked as a cabinetmaker and in the railways, and was an official in the Furniture Trades' Union, being a delegate to and later president of the Trades and Labor Council.

In 1916 he was a foundation member of the Industrial Vigilance Council and a delegate to the Anti-Conscription League, and from 1913 to 1917 he served on the central executive of the Australian Labor Party (vice-president 1916–17).

In 1917 he was elected to the New South Wales Legislative Assembly as the member for Annandale, transferring to Murray with the introduction of proportional representation in 1920.