Tjitske Siderius (born 24 September 1981 in Groenlo) is a Dutch politician. She was a member of the House of Representatives of the Netherlands for the Socialist Party between 3 September 2013 and 26 November 2013, temporarily replacing Sadet Karabulut, who went on maternity leave. From 6 February 2014 Siderius temporarily replaced Renske Leijten who went on maternity leave. When Paulus Jansen resigned in April 2014, Siderius became his permanent replacement on 14 May 2014.