Kathalijne Maria Buitenweg (born 27 March 1970) is a Dutch politician for the GreenLeft who served as a member of the House of Representatives between 2017 and 2021.

In 1991 she became a member of the executive of the European Coordination Bureau of International Youth Organisations, and was elected vice-chairperson in 1993, which she remained until 1995.

In reaction to the motion "we want to choose" which was carried by the GreenLeft party Congress Buitenweg decided to become candidate in the last minutes before the election.

In 2007 she joined the Committee on the Environment, Public Health and Food Safety as a substitute In 2008 she announced that she would not seek a third term in the European Parliament.

[6] In January 2021 Buitenweg was nominated and subsequently confirmed as member of the Dutch Council of State, where she will start in June 2021.