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
Born
John William O'Brien

(1881-01-23)23 January 1881
Clonakilty, County Cork, Ireland
Died31 October 1968(1968-10-31) (aged 87)
Bray, County Wicklow, Ireland
Resting placeGlasnevin cemetery, Dublin
Political 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.