7 March – Changes to the Liturgy of the Catholic Mass were introduced. Mass was said in the vernacular (English) for the first time instead of in Latin.
18 March – The Northern Minister for Agriculture, Harry West attended a meeting with his Southern counterpart, Charles Haughey, in Dublin.
7 April – 1965 Irish general election: The ruling Fianna Fáil party led by Seán Lemass gained a majority. This was the first Irish general election to be covered on television by state broadcaster Telefís Éireann. The Clann na Talmhan party did not contest the election and was wound up. Members of the 18th Dáil assembled on 21 April.
18 April – The Gaelic Athletic Association Congress in Dublin decided that the ban on foreign games was to remain.