Andreas Raphael Blass (born October 27, 1947) is a mathematician, currently a professor at the University of Michigan.

He received his Ph.D. in 1970 from Harvard University, with a thesis on Orderings of Ultrafilters written under the supervision of Frank Wattenberg.

[3] In 1984 Blass proved that the existence of a basis for every vector space is equivalent to the axiom of choice.

He made important contributions in the development of the set theory of the reals and forcing.

He has authored more than 200 research articles in mathematical logic and theoretical computer science, including: