James Connolly (Irish name: Séamas Ó Conghaile or Ó Conghalaigh; June 5, 1868 – May 12, 1916) was an Irish-Scots socialist leader. He was born in Edinburgh, Scotland, to Irish immigrant parents. He left school for working life at the age of 11, but despite this he would become one of the leading left-wing theorists of his day. Though proud of his Irish background he also took a role in Scottish politics. In addition, he studied the neutral international language, Esperanto.

By 1892, he was an important figure in the Scottish Socialist Federation, acting as its secretary from 1895, but by 1896 he had left the army and established his Irish Socialist Republican Party (ISRP). While active as a socialist in Great Britain Connolly was among the founders of the Socialist Labour Party which split from the Social Democratic Federation in 1903. He was right hand man to James Larkin in the Irish Transport and General Workers Union. In 1913, in response to the Lockout, he, along with an ex-British officer Jack White, founded the Irish Citizen Army (ICA), an armed and well-trained body of labour men whose aim was to defend workers and strikers, particularly from the frequent brutality of the Dublin Metropolitan Police. Though they only numbered about 250 at most, their goal soon became the establishment of an independent and socialist Irish nation. He founded the Irish Labour Party in 1912 and was a member of the National Executive of the Irish Labour Party when he was executed in 1916.

When the Easter Rising occurred on April 24, 1916, Connolly was Commandant of the Dublin Brigade, and as the Dublin brigade had the most substantial role in the rising, he was de facto Commander in Chief. Following the surrender he was executed by the British at Kilmainham Gaol in Dublin, although he was so badly injured from the fighting that he was unable to stand before the firing squad and was therefore shot in a chair. He was survived by his wife and numerous children.

His legacy in Ireland is mainly due to his contribution to the nationalist cause and his Marxism has been largely overlooked by mainstream histories (although his legacy as a socialist has been claimed by the Labour Party, the Communist Party of Ireland, the SWP, the Socialist Party and a variety of other left-wing and left-republican groups). However, despite claims to the contrary, Connolly's writings show him to be first and foremost a Marxist thinker. In several of his works he rails against what he calls the bourgeois nationalism of those who claimed to be Irish patriots.