Joseph John O'Connor (c.1880 – 2 February 1959) was an Irish revolutionary, soldier and politician. O'Connor was born in the 1880s and remembered seeing Charles Stewart Parnell as a child. He joined the Irish Volunteers in 1913 and by 1916 he was a captain in command of A Company, 3rd Battalion, Dublin Brigade under Éamon de Valera. When the vice-commandant failed to show for the 1916 Easter Rising de Valera made O'Connor his second in command. O'Connor remained with his company and de Valera at Bolands Mill until they became the last battalion to surrender. He was imprisoned at Frongoch internment camp in Wales and released in the 1917 amnesty.