Geir Ellingsrud (born 29 November 1948) is professor of mathematics at the University of Oslo, where he specialises in algebra and algebraic geometry. He took the cand.real. degree at the University of Oslo in 1973, and the doctorate at Stockholm University in 1982. He was a lecturer at Stockholm University from 1982 to 1984, associate professor at the University of Oslo from 1984 to 1989, professor at the University of Bergen from 1989 to 1993 and at the University of Oslo since 1993. He has been a visiting scholar in Nice, Paris, Bonn and Chicago. He has edited the journals Acta Mathematica and Normat.