William X. O’Brien (23 January 1881 – 31 October 1968) was an Teachta Dála (TD) and trade unionist in Ireland.
Born in Clonakilty, County Cork, O’Brien moved with his family to Dublin in 1897, and quickly became involved in the Irish Socialist Republican Party (ISRP). O’Brien is described as “a very significant figure in the ISRP” by the historian of the ISRP, David Lynch.
A close friend and associate of James Connolly, O’Brien helped establish the Irish Transport and General Workers’ Union in 1909, and was instrumental in the Dublin Lockout strike in 1913.
A member of the Irish Neutrality League, and Anti-Conscription Committee, during the Great War, O’Brien was interned on several occasions by the Dublin Castle government. During one of these instances, he stood in the Stockport by-election, 1920, but was refused a release to campaign in it.
With the formation of the Irish Free State, O’Brien was elected as TD for Dublin South at the 1922 general election, and again for Tipperary in June 1927 and again in 1937.
An important figure in the Labour Party in Ireland in its formative days, O’Brien resisted Jim Larkin’s attempt to gain control of the Party on release from prison. Taking Larkin to court over his occupation of ITGWU headquarters, the Larkin-O’Brien feud resulted in a split within the labour and trade union movements, and the formation of the Irish Congress of Trade Unions.
William Cosgrave while President of the Executive Council of the Free State government notably turned down a plea for asylum in Ireland for Leon Trotsky made by O’Brien. In 1930, Cosgrave told him:
“I could see no reason why Trotsky should be considered by us. Russian bonds had been practically confiscated. He said there was to be consideration of them. I said it was not by Trotsky, whose policy was the reverse. I asked his nationality. Reply Jew. They were against religion (he said that was modified). I said not by Trotsky. He said he had hoped there would be an asylum here as in England for all. I agreed that under normal conditions, which we had not here, that would be all right. But we had no touch with this man or his Government, nor did they interest themselves in us in his ‘day’.
Active in politics and the trade union movement into his 60s, O’Brien retired in 1946 and died on 31 October 1968.