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. Henri Swinkels then became the temporary replacement for Leijten. Her term in the House ended on 23 March 2017.