Erik Magnus Alfsen (13 May 1930 – 20 November 2019) was a Norwegian mathematician. He is the author of Compact Convex Sets and Boundary Integrals, published in 1971. He was a board member of the Norwegian Research Council for Science and the Humanities (NAVF) for two years, and has also been involved in and the Pugwash Conferences. He was a member of the Norwegian Academy of Science and Letters, the Royal Norwegian Society of Sciences and Letters and the Royal Danish Academy of Sciences and Letters.