Andrew Michael Odlyzko (Andrzej Odłyżko) (born 23 July 1949) is a Polish-American mathematician and a former head of the University of Minnesota's Digital Technology Center and of the Minnesota Supercomputing Institute. He began his career in 1975 at Bell Telephone Laboratories, where he stayed for 26 years before joining the University of Minnesota in 2001.

Odlyzko received his B.S. and M.S. in mathematics from the California Institute of Technology and his Ph.D. from the Massachusetts Institute of Technology in 1975.

In the field of mathematics he has published extensively on analytic number theory, computational number theory, cryptography, algorithms and computational complexity, combinatorics, probability, and error-correcting codes. In the early 1970s, he was a co-author (with D. Kahaner and Gian-Carlo Rota) of one of the founding papers of the modern umbral calculus. In 1985 he and Herman te Riele disproved the Mertens conjecture. In mathematics, he is probably known best for his work on the Riemann zeta function, which led to the invention of improved algorithms, including the Odlyzko–Schönhage algorithm, and large-scale computations, which stimulated extensive research on connections between the zeta function and random matrix theory.

As a direct collaborator of Paul Erdős, he has Erdős number 1.

More recently, he has worked on communication networks, electronic publishing, economics of security and electronic commerce.

In 1998, he and Kerry Coffman were the first to show that one of the great inspirations for the Internet bubble, the myth of "Internet traffic doubling every 100 days," was false.

In the paper "Content is Not King", published in First Monday in January 2001, he argues that

In 2012, he became a fellow of the International Association for Cryptologic Research and in 2013 of the American Mathematical Society.