The O’Connell School is a secondary and primary school for boys located on North Richmond Street in Dublin, Ireland. The school, named in honour of the leader of Catholic Emancipation, Daniel O’Connell, has the distinction of being the oldest surviving Christian Brothers school in Dublin, having been first established in 1829. It is now under the trusteeship of the Edmund Rice Schools Trust.

The school offers the Junior Certificate and Leaving Certificate programmes.

A number of significant figures in Irish public life attended O'Connell's School.

• Philip Chevron - musician, songwriter and member of the Pogues
• Paul Harrington - singer songwriter, Eurovision winner 1994
• Michael Holohan – composer, member and former chair of Aosdána.
• James Joyce – writer who briefly attended the school; the school is mentioned in Dubliners in the story "Araby"
• Pat Kenny – radio and television presenter
• Barry Keoghan – film and television actor
• Thomas Kinsella – poet and playwright
• Declan Masterson – multi-instrumentalist, composer, former Musical Director at Riverdance
• Colm Meaney – film and television actor
• Michael O'Hehir – radio broadcaster and sports commentator
• Mícheál Ó Muircheartaigh – sports commentator who briefly taught at the O'Connell School
• Luke Kelly – lead singer of folk group The Dubliners
• Brendan Cauldwell - actor

• Bill Cullen – Irish businessman, philanthropist and star of The Apprentice

• Peter V. Delaney – Irish colorectal surgeon
• John Hooper – first Director of the Statistics Branch of the Department of Industry and Commerce in Ireland
• William Mulholland – Irish-American dam civil engineer
• Joseph Ó Ruanaidh – scientist

• Maurice Ahern – Politician and Lord Mayor of Dublin 2000–2001
• Brendan Bracken – British Minister of Information during the Second World War
• Ray Burke – Fianna Fáil politician
• Éamonn Ceannt – Irish Nationalist; one of the 1916 Easter Rising signatories
• John A. Costello – Taoiseach
• Tom Kettle – Nationalist MP and Irish Volunteer who died in the First World War
• Seán Lemass – Taoiseach
• P. J. Mara – Fianna Fáil public affairs consultant
• Seán T. O'Kelly – second President of Ireland
• Ernie O'Malley -Irish revolutionary and author
• John Stafford – TD and former Lord Mayor of Dublin
• Nial Ring – Politician and Lord Mayor of Dublin 2018–2019
• Lorcan Sherlock – Politician and Lord Mayor of Dublin 1912–1915

• Abraham Brownrigg - Bishop of Ossory (1884–1928)
• James Kavanagh – University College Dublin professor and bishop in the Dublin Diocese

• Tom Farquharson - goalkeeper for Cardiff and Ireland, dubbed the penalty king
• Bertie Kerr – Ireland football international and bloodstock agent
• Paddy Neville – cricketer
• Troy Parrott – professional footballer
• Ronnie Delaney – Olympic Gold Medallist
• Stephen Elliott - Professional footballer
• Niall Brophy - athlete and rugby player

• Paddy Finucane – World War II top-scoring fighter pilot ace in the RAF
• Frank Flood – IRA officer executed in 1921 during the War of Independence; one of The Forgotten Ten
• Seán Heuston – a leading member of the 1916 Easter Rising

• Official website