Nicholas John Gillespie is an American libertarian journalist who was editor-in-chief of Reason magazine from 2000 to 2008 and editor-in-chief of Reason.com and Reason TV from 2008 to 2017. Gillespie originally joined Reason's staff in 1993 as an assistant editor and ascended to the top slot in 2000. He is currently an editor-at-large at Reason. Gillespie has edited one anthology, Choice: The Best of Reason.

Reason is an American libertarian monthly magazine published by the Reason Foundation, with the tagline "Free Minds and Free Markets". The magazine aims to produce independent journalism that is "outside of the left/right echo chamber." The magazine has a circulation of around 50,000.