Xavier Leroy (born 15 March 1968) is a French computer scientist and programmer.

[1] Leroy was admitted to the École normale supérieure in Paris in 1987, where he studied mathematics and computer science.

He is the leader of the CompCert project that develops an optimizing compiler for the C programming language, formally verified in Coq.

Leroy was also the original author of LinuxThreads, the most widely used threading package for Linux versions prior to 2.6[broken anchor].

Linux 2.6[broken anchor] introduced NPTL, with much more extensive support from the kernel, to replace LinuxThreads.