Events from the year 1899 in Ireland.

• 14 January – Ocean liner RMS Oceanic is launched by Harland and Wolff in Belfast.
• 4 March – the first issue of Arthur Griffith and William Rooney's nationalist newspaper, The United Irishman, is published.^[1]
• 6 September – the foundation stone of St Anne's Cathedral, Belfast, is laid by the Countess of Shaftesbury.
• 11 October – the Second Boer War begins in South Africa. Major John MacBride raises the Irish Transvaal Brigade to aid the Boers. Nationalist Member of Parliament Michael Davitt withdraws from the House of Commons of the United Kingdom in protest at the war.

• 8 May – the Irish Literary Theatre, founded by W. B. Yeats, Augusta, Lady Gregory, George Moore and Edward Martyn, stages its first performance, a version of Yeats' verse drama The Countess Cathleen, at the Antient Concert Rooms in Great Brunswick Street, Dublin.
• Somerville and Ross publish their first collection of humorous stories Some Experiences of an Irish R.M.
• W. B. Yeats publishes The Wind Amongst the Reeds.
• The Rathmines and Rathgar music society is founded.

• 18 January – Sir Anthony Esmonde, 15th Baronet, Fine Gael TD and MEP (died 1981).
• 21 January – John Bodkin Adams, general practitioner in Eastbourne cleared of murdering one of his patients (died 1983).
• 13 March – Arthur Duff, composer and conductor (died 1956).
• 10 April – Liam Ó Buachalla, Cathaoirleach of Seanad Éireann 1951–1954 and 1957–1969 (died 1970).
• 26 April – Jimmy O'Dea, comedian (died 1965).
• 25 May – Lory Meagher, Kilkenny hurler (died 1973).
• 7 June – Elizabeth Bowen, novelist and short story writer (died 1973).
• 20 June – Robert Donovan, cricketer (died 1932).
• 4 July – Alexander Armstrong, naval surgeon, explorer and author (born 1818).
• 15 July – Seán Lemass, Fianna Fáil TD and founder member, Cabinet Minister and Taoiseach (died 1971).
• 9 September – Arland Ussher, English-born academic, essayist and translator (died 1980).
• 22 September – Mick Gill, Galway and Dublin hurler (died 1980).
• 25 October – Micheál MacLiammóir, born Alfred Willmore, actor and dramatist (born in London; died 1978).
• 26 November – Jacko Heaslip, cricketer (died 1966).
• 10 December – Garrett Howard, Dublin and Limerick hurler (died 1995).
• Full date unknown
  • Tommy Coleman, Irish volunteer (died 1988).
  • Patrick Giles, Fine Gael TD (died 1965).
  • Paddy McLogan, Sinn Féin President (died 1964).
  • David Neligan, policeman, "The Spy in the Castle" for Michael Collins (died 1983).
  • Eugene O'Mahony, entomologist and museum curator (died 1951).

• 16 March – Alexander Balloch Grosart, Presbyterian minister and literary editor (born 1827 in Scotland)
• 19 March – Patrick Walsh, journalist, politician and mayor of Augusta, Georgia (born 1840).
• 16 May – Frederick McCoy, palaeontologist and museum administrator in Australia (born 1817).
• 5 June – Margaret Anna Cusack, nun, writer and founder of the Sisters of St. Joseph of Peace (born 1832).
• 18 October – Eugene O'Growney, priest and scholar (born 1863).
• 8 November – Thomas Newenham Deane, architect (born 1828).
• 17 December – Walter Shanly, civil engineer, author, businessman and politician in Canada (born 1817).

• 1899 in Scotland
• 1899 in Wales