Catharina Johanna Elise (Nine) Kooiman (born December 9, 1980 in De Meern, Utrecht) is a Dutch politician and former social worker. As a member of the Socialist Party (Socialistische Partij) she has been an MP since June 17, 2010. She focuses on matters of youth and family law. Kooiman was born in neighbourhood De Meern in the city of Utrecht.
From 2007 to 2010 she was a member of the municipal council of Nieuwegein.
Kooiman studied social work and public services at the Hogeschool De Horst in Driebergen.