Séamus Brennan (born February 16, 1948) is a senior Irish Fianna Fáil politician. He is currently a Teachta Dála for Dublin South and Minister for Social & Family Affairs. He has previously served as Minister for Tourism & Transport (1989-1991), Minister for Tourism, Transport & Communications (1991-1992), Minister for Education (1992-1993) and Minister for Transport (2002-2004).

Séamus Brennan was born in Galway and was educated at St. Joseph's Secondary School, Galway, University College Galway and University College Dublin where he studied Economics and Commerce. He found an interest in politics during his teens when he canvassed for Fianna Fáil during elections. In the early 1970's he succeeded Tommy Mullins as Secretary General of Fianna Fáil. He began to revamp the party structure with the setting up of a national executive. Brennan studied and was impressed by the Presidential Election in the United States in 1976. He applied new techniques such as marketing strategies and opinion polls to the Irish general election the following year. This resulted in the biggest ever parliamentary majority for any party. Fianna Fáil and Jack Lynch were back in power. Brennan was appointed to Seanad Éireann.

In 1979 he supported George Colley in the Fianna Fáil leadership contest, caused by the retirement of Jack Lynch. However, Charles Haughey was narrowly successful and a new Secretary General of the party was appointed. In 1981 Brennan was elected to Dáil Éireann and has been returned at every election ever since then. In the early 1980's he was a prominent member of the Gang of 22 who tried unsuccessfully to wrestle control of the Fianna Fáil party from Charles Haughey. It was expected that Brennan would join the Progressive Democrats when thay were founded by Desmond O'Malley in 1985 but instead he remained with Fianna Fáil.

In 1987 Charles Haughey's Fianna Fáil were back in power and Brennan was rewarded by being appointed Minister of State with responsibility for Trade and Marketing. In 1989 he became a full Cabinet Minister when he was appointed Minister for Tourism & Transport. In 1991 the Communications portfolio came under the control of Brennan. In 1992 Albert Reynolds succeeded Haughey as Taoiseach. Brennan was one of the few ministers in Charles Haughey's Cabinet who remained in Reynolds' new government. He was appointed Minister for Education. In 1993 the Fianna Fáil-Labour coalition came to power and Brennan was demoted to Minister of State for Commerce & Technology.

In 1995 the new Fianna Fáil leader, Bertie Ahern named his new Front Bench. Brennan became Fianna Fáil spokesman for Transport, Energy & Communications. In 1997 Fianna Fáil returned to power and Brennan became Government Chief Whip and Minister of State at the Departments of An Taoiseach and Defence. He was promoted to Minister for Transport in 2002.

In the cabinet reshuffle of September 2004, Brennan was moved to the post of Minister for Social & Family Affairs. It is an open secret that this move was contrary to Brennan's wishes, and was widely seen as a demotion. It has also been stated that Brennan was originally going to be sacked from the government and would have been if it wasn't for the intervention of the Tánaiste, Mary Harney.

|- style="text-align: center;" | width="30%" |Preceded by:
the office of Minister for Tourism & Transport | width="40%" style="text-align: center;" |Minister for Tourism, Transport & Communications
1991–1992 | width="30%" |Succeeded by:
Máire Geoghegan-Quinn

|- style="text-align: center;" | width="30%" |Preceded by:
Noel Davern | width="40%" style="text-align: center;" |Minister for Education
1992–1993 | width="30%" |Succeeded by:
Niamh Bhreathnach

|- style="text-align: center;" | width="30%" |Preceded by:
Jim Higgins | width="40%" style="text-align: center;" |Minister of State at the Department of the Taoiseach
1997–2002 | width="30%" |Succeeded by:
Mary Hanafin

|- style="text-align: center;" | width="30%" |Preceded by:
Mary O'Rourke | width="40%" style="text-align: center;" |Minister for Tourism & Transport
2002–2004 | width="30%" |Succeeded by:
Martin Cullen

|- style="text-align: center;" | width="30%" |Preceded by:
Mary Coughlan | width="40%" style="text-align: center;" |Minister for Social & Family Affairs
2004– | width="30%" |Succeeded by:
Current Incumbent