The Clay Mathematics Institute (CMI) is a private, non-profit foundation, based in Cambridge, Massachusetts. The institute is dedicated to increasing and disseminating mathematical knowledge. It gives out various awards and sponsorships to promising mathematicians. Boston businessman Landon T. Clay and his wife, Lavinia D. Clay started it in 1998. Harvard University mathematician Arthur Jaffe was the first president of CMI.
The institute is best known for its Millennium Prize Problems, a list of the seven most important unsolved mathematical questions. Of these, only the Poincaré conjecture has since been solved. The Clay Institute also does other things, including a postdoctoral program (ten Clay Research Fellows are supported each year) and an annual summer school, the proceedings of which are published jointly with the American Mathematical Society.