Jeffrey Outlaw Shallit (born October 17, 1957) is an American computer scientist and mathematician.

His father was journalist Joseph Shallit, the son of Jewish immigrants from Vitebsk, Russia (now in Belarus).

His doctoral thesis was entitled Metric Theory of Pierce Expansions and his advisor was Manuel Blum.

In 1997, he gained attention for the publication on the Internet of Holocaust Revised: Lies of Our Times (also called the Shallit Report), a reprint of an article he had written for a Waterloo student publication in 1993, which detailed the backgrounds and past statements of various persons whom he accused of being Holocaust deniers, notably David Irving, Fred A. Leuchter, and Eustace Mullins.

As of 2024[update] Shallit is a Professor in the School of Computer Science at the University of Waterloo[4] and the editor-in-chief of the Journal of Integer Sequences.