Derrick Samuel Frederick Crothers (born 24 June 1942 in Belfast, died 15 January 2021) was a Northern Irish mathematician, physicist and former politician. Crothers grew up in Cookstown, Tyrone, from the age of 7, and studied at Rainey Endowed School, where he won the top mathematics and Science State Exhibition prize in 1959. He then read mathematics at Balliol College, Oxford, before obtaining his doctorate in 1966 at Queen's University Belfast (QUB) on "Theoretical Studies of Inelastic Atomic Collisions" under David Bates In the following years, he lectured at QUB, undertook research at University College London, worked as a tutor for the Open University, and was elected as a Fellow of the Institute of Physics.