Events from the year 1823 in Ireland.

• Catholic Association formed by Daniel O'Connell, to further Catholic Emancipation.^[1][2]
• October – HMS Essex, a former American frigate of 1799, is hulked at Cork to serve as a prison ship; from 1824 to 1834 she serves in this capacity at Kingstown.^[3]

• 5 August – the Royal Hibernian Academy of Painting, Sculpture, and Architecture is established by letters patent in Dublin.^[4]

• 1 January – Edward Butler, lawyer and politician in Australia (died 1879).
• 12 January – James Donnelly, Bishop of the Diocese of Clogher (died 1893).
• 23 January – Abraham Fitzgibbon, railway civil engineer in the British empire (died 1887 in England)
• 26 March – Ann Jellicoe, educationalist (died 1880).
• 7 July – John Kells Ingram, poet, scholar, economist and historian of economic thought (died 1907).
• 7 September – Kevin Izod O'Doherty, transported to Australia in 1849, physician and politician (died 1905).
• 10 September – James O'Connor, first Archbishop of the Roman Catholic Archdiocese of Omaha (died 1890).
• 16 September – James O'Reilly, lawyer and politician in Canada (died 1875).

  Full date unknown

  • Thomas Devin Reilly, revolutionary, Young Irelander and journalist (died 1854).
  • John Ryan, soldier, recipient of the Victoria Cross for gallantry in 1857 at Lucknow, India, killed in action (died 1858).

• 21 February – Charles Wolfe, poet (born 1791).
• 17 September – John Shaw, Captain in the United States Navy (born 1773).

• 1823 in Scotland
• 1823 in Wales