Leinster was a European Parliament constituency in Ireland between 1979 and 2004. It elected three Members of the European Parliament (MEPs) in the 1979, 1984 and 1989 elections and four MEPs in the elections of 1994 and 1999 using the single transferable vote form of proportional representation (PR-STV).
The constituency was created in 1979 for the first direct elections to the European Parliament. It comprised the counties of Carlow, Kildare, Kilkenny, Laois, Longford, Louth, Meath, Offaly, Westmeath, Wexford and Wicklow from the historic province of Leinster excluding the County Dublin area. It was abolished under the European Parliament Elections (Amendment) Act 2004 and succeeded by the new East constituency.
Mark Clinton stepped down and was replaced by his party colleague Patrick Cooney.