Sir James O'Connor, KC PC (I) (1 April 1872 – 29 December 1931) was an Irish solicitor, barrister and judge. He was appointed Solicitor-General for Ireland in 1914, Attorney-General for Ireland in 1917, and a judge of the Supreme Court of Judicature of Ireland in 1918. After his enforced retirement in 1924, he practised at the English bar until 1929, when he returned to Ireland and was readmitted to practice as a solicitor, a controversial move necessitating a leading judgment on the standard of professional conduct to be expected of a former judge.