Sylvester A. Barrett (18 May 1926 – 8 May 2002) was an Irish Fianna Fáil politician. He served under Jack Lynch and Charles Haughey as Minister for the Environment (1977–1980) and Minister for Defence (1980–1981).
Sylvester Barrett was born in Darragh, near Ennis, County Clare in 1926. His father, who was a founder-member of the Fianna Fáil party, died while Barrett was still very young. As a result he was raised by an uncle and aunt. Barrett was educated at Ballyea National School and St. Flannan's College in Ennis. He studied engineering at University College Galway though did not complete his studies. He was a cadet in the Irish Army and later worked as a rate collector and an auctioneer.
He was first elected to Dáil Éireann on 14 March 1968 at the Clare by-election in the Clare constituency, following the death of Fine Gael TD William Murphy. Barrett topped the poll at the general election the following year. At the 1973 general election, Fianna Fáil lost power to a Fine Gael–Labour Party coalition government under Liam Cosgrave, and Barrett was appointed to the party's front bench as spokesperson on Transport and Power. After Fianna Fáil's landslide victory at the 1977 general election, he was appointed to the Cabinet as Minister for the Environment.
In 1979, Barrett supported George Colley in the Fianna Fáil leadership election. Charles Haughey was the eventual victor, but Barrett was retained in the cabinet in the Environment position. Following a reshuffle in 1980, he was appointed Minister for Defence. After the February 1982 general election, Fianna Fáil were returned to power but Barrett was not appointed to the Cabinet. However, several weeks later he was appointed a Minister of State at the Department of Finance.
In October 1982, when Charlie McCreevy put down a motion of no confidence in Haughey's leadership, Barrett was the only Minister of State to support it. Haughey survived, and while Barrett was a member of the so-called "Gang of 22" he was not sacked from his office. Indeed the following month he topped the poll at the November 1982 general election.
Fianna Fáil were out of power again and Barrett was appointed to the front bench as spokesperson on Defence. He remained there until 1984 when he won a seat in the Munster constituency at the 1984 European Parliament election and was replaced on the Front Bench by Noel Treacy. He decided not to contest the 1989 European Parliament election and retired from politics. He died in 2002.