David James Thouless FRS (/ˈθaʊlɛs/; 21 September 1934 – 6 April 2019) was a British condensed-matter physicist. He was the winner of the 1990 Wolf Prize and a laureate of the 2016 Nobel Prize for physics along with F. Duncan M. Haldane and J. Michael Kosterlitz for theoretical discoveries of topological phase transitions and topological phases of matter.