Hans Kennert Mattias Hedarv Karlsson (born 17 August 1977) is a Swedish politician who served as Leader of the Sweden Democrats in the Riksdag from September 2014 to November 2019. He has been a Member of the Riksdag (SD) for Scania County since October 2010. He previously served as Leader of the Sweden Democrats from 2014 to 2015. He currently heads the conservative think-tank Oikos.