Thomas W. Gilligan is an American economist who was the Tad and Dianne Taube Director of the Hoover Institution at Stanford University from 2015 to 2020. Prior to taking over as head of the Stanford-based think tank, he served as dean of the McCombs School of Business at The University of Texas at Austin. Gilligan previously held a variety of positions at the University of Southern California from 1987 until 2008.

The Hoover Institution is an American public policy think tank which promotes personal and economic liberty, free enterprise, and limited government. While the institution is formally a unit of Stanford University, it maintains an independent board of overseers and relies on its own income and donations. It is widely described as conservative, although its directors have contested the idea that it is partisan.