The Electoral (Amendment) Act, 1983 (No. 36/1983) was a law in Ireland which provided for parliamentary constituencies in the 25th Dáil (1987–1989) and the 26th Dáil (1989–92). The 25th Dáil Éireann was elected at the 1987 general election on 17 February 1987, and the 26th Dáil Éireann was elected at the 1989 general election on 15 June 1989.
This Act replaced the Electoral (Amendment) Act 1980, which defined the constituencies used for the 22nd Dáil (1981–82), 23rd Dáil (February–November 1982) and the 24th Dáil (1982–87). It was itself replaced by the Electoral (Amendment) Act 1990, which created a new pattern of constituencies for the 27th Dáil (elected in 1992).