Dean Harold Jaensch AO (27 October 1936 – 17 January 2022) was an Australian political scientist and a Professor of Political and International Studies at The Flinders University of South Australia. Jaensch was awarded a Bachelor of Arts (Honours), a Master of Arts and PhD from the University of Adelaide. He wrote many highly regarded books (14) on political parties, electoral politics and voting behaviour in Australian politics, and also focussed on South Australian and Northern Territory politics, federalism within the Anglosphere and empirical methodology.