David William Masser (born 8 November 1948) FRS is Professor Emeritus in the Department of Mathematics and Computer Science at the University of Basel.

With Joseph Oesterlé in 1985, Masser formulated the abc conjecture, which has been called "the most important unsolved problem in Diophantine analysis".

and Ph.D. at the University of Cambridge,[3] with a doctoral thesis under the supervision of Alan Baker titled Elliptic Functions and Transcendence.

[3] He then moved to the Mathematics Institute at the University of Basel and became emeritus there in 2014.

[6] Masser was an invited speaker at the International Congress of Mathematicians in Warsaw in 1983.