William O'Brien (trade unionist)

William O'Brien
O'Brien, c. 1930
Teachta Dála
In office
July 1937 – June 1938
In office
June 1927 – September 1927
ConstituencyTipperary
In office
June 1922 – August 1923
ConstituencyDublin South
Personal details
BornJohn William O'Brien
(1881-01-23)23 January 1881
Died31 October 1968(1968-10-31) (aged 87)
Resting placeGlasnevin cemetery, Dublin
Party
OccupationTrade union leader

William O'Brien (23 January 1881 – 31 October 1968) was a politician and trade unionist in Ireland. While rarely dominating the political spotlight, O'Brien was incredibly powerful and influential behind the scenes, maintaining a firm grip over Ireland's trade unions for many decades. Besides his leadership in the trade unions, O'Brien was a founder, alongside James Larkin and James Connolly, of the Labour Party of Ireland. In later years a rift formed between Larkin and O'Brien that would last the rest of their lives and often divide the labour movement in Ireland.