Mark Killilea, Jnr (born 5 September 1939) is a former Irish Fianna Fáil politician. In a 30-year political career, served as a Teachta Dála (TD) and Member of the European Parliament (MEP) and also as a Senator.
Mark Killilea was born in Tuam, County Galway in 1939. He married Anne Severs in 1966. His father Mark Killilea, Snr was a Fianna Fáil TD and a founder-member of the party. Killilea Jnr was educated locally and first held political office in August 1969, when he was elected to Seanad Éireann on the Labour Panel and re-elected in 1973. He failed to be elected to Dáil Éireann on his first attempt when he stood in Galway North–East at the 1973 general election, but at the 1977 general election he won a seat in the new Galway East constituency. The election was a landslide for Fianna Fáil and in particular showed the popularity of the party leader Jack Lynch.
However, after just two years Lynch's fortunes had changed. Along with Jackie Fahey, Tom McEllistrim, Seán Doherty and Albert Reynolds, Killilea was one of the so-called "gang of five" that lobbied the parliamentary party for support for Charles Haughey in the event of the retirement of Jack Lynch. This group was determined that the leadership should not pass to George Colley, Lynch's apparent successor. Haughey went on to win the leadership contest and became Taoiseach in December 1979.