Joel Spencer (born April 20, 1946) is an American mathematician. He is a combinatorialist who has worked on probabilistic methods in combinatorics and on Ramsey theory. He received his doctorate from Harvard University in 1970, under the supervision of Andrew Gleason. He is one of the few people with an Erdős number of 1. He is currently (as of 2013 ) a professor at the Courant Institute of Mathematical Sciences of New York University.
In 2012 he became a fellow of the American Mathematical Society.
- Probabilistic methods in combinatorics, with Paul Erdős, New York: Academic Press, 1974.
- Ramsey theory, with Bruce L. Rothschild and Ronald L. Graham, New York: Wiley, 1980; 2nd ed., 1990.
- Ten lectures on the probabilistic method, Philadelphia: Society for Industrial and Applied Mathematics, 1987; 2nd ed., 1994.
- The probabilistic method, with Noga Alon, New York: Wiley, 1992; 2nd ed., 2000; 3rd ed., 2008
- The strange logic of random graphs, Berlin: Springer-Verlag, 2001.