Thomas Carolus de Graaf is a Dutch jurist and politician. First elected to the House of Representatives in 1994, he became parliamentary leader of the Democrats 66 (D66) in 1997, and party leader the following year. He became Deputy Prime Minister of the Netherlands in 2003, but resigned two years later following the defeat of his bill aiming to introduce direct mayoral elections. He subsequently served as mayor of Nijmegen between 2007 and 2012, and was elected to the Senate in 2011, leading his party's Senate group from 2015 until 2018. On 1 November 2018, he was appointed Vice-President of the Council of State, serving in this capacity until 1 July 2026.