Ian Hugh Sloan AO (born 17 June 1938, Melbourne) is an Australian applied mathematician.
He was educated at the University of Melbourne (BSc 1958, BA (hons) 1960), University of Adelaide (MSc, 1961) and University College London, where he was supervised by renowned mathematical physicist Sir Harrie Massey, and earned his PhD in 1964.
He was a research scientist for the Colonial Sugar Refining company 1964–5, and since 1965 has been at the University of New South Wales, where he has been Scientia Professor since 1999.
He served as Head of the School of Mathematics from 1986 to 1990 and from 1992 to 1993.His early work was in theoretical nuclear physics, but he moved to applied mathematics, especially numerical analysis.
Sloan has published more than 200 papers covering areas such as the numerical solution of integral equations, numerical integration and interpolation, boundary integral equations, approximation theory, multiple integration, continuous complexity theory and other parts of numerical analysis and approximation theory.
He has made important contributions to the theory of numerical integration in many dimensions, in recent years concentrating on quasi-Monte Carlo methods.After serving as Vice-President and President elect 2017–2018, Sloan became President of the Royal Society of New South Wales in 2018, taking over from Professor D.