Marianne Thyssen was awarded a law degree by the Catholic University of Leuven (KUL). She then joined the law faculty at the Catholic University of Leuven (KUL) as an assistant lecturer. She then joined UNIZO (organisation for the self-employed and SMEs) as a legal advisor. She later became head of a research department and Secretary-General at UNIZO. She was then appointed legal assistant in the office of the State Secretary for Health. She was a member of the governing body of the European Foundation for the Improvement of Living and Working Conditions in Dublin from 1988 to 1991. She served as Vice-President of the CD&V (Christian Democratic and Flemish) Party from 1996 to 2001 and as a member of the CD&V governing board from 2001 to 2008. She was Chair of the CD&V governing board from 2008 until 2010. She was a member of the Oud-Heverlee Municipal Council from 1994 to 2008 and became the first Deputy Mayor of Oud-Heverlee in 2001. She has been a Member of the European Parliament since 1991. In that time she became the first Vice-Chairwoman of the EPP Group and is currently the leader of the Belgian delegation in the EPP Group.