Seán O'Mahony (also John O'Mahoney) (20 October 1872 – 28 November 1934) was an Irish Sinn Féin politician and member of the First and Second Dáil. He was born as John Mahony in Logan Street, Thomastown, County Kilkenny, to James Mahony, a tailor, and Mary Cantwell. A successful businessman he was a tea merchant and a commercial traveller. His company, John O'Mahoney & Co., was located on Middle Abbey St., and was destroyed during the 1916 Easter Rising. It subsequently reestablished on Parnell Square. He subsequently purchased and ran Fleming's Hotel which was located at 31–32 Gardiner Place, Dublin. A close friend of Arthur Griffith, he became an organiser for Sinn Féin and was elected to Dublin Corporation for the party.