Sir John Macleod Ball, FRSE FRS (born 1948) is Sedleian Professor of Natural Philosophy at the University of Oxford. He was the President of the International Mathematical Union from 2003–06 and a Fellow of Queen's College, Oxford. He was educated at the University of Cambridge and Sussex University, and prior to taking up his Oxford post was a professor of mathematics at Heriot-Watt University in Edinburgh.He was awarded the Sylvester Medal by the Royal Society in 2010 for his seminal work in mechanics and nonlinear analysis and his encouragement of mathematical research in developing countries.