Libertarian paternalism is the idea that it is both possible and legitimate for private and public institutions to affect behavior while also respecting freedom of choice, as well as the implementation of that idea. The term was coined by behavioral economist Richard Thaler and legal scholar Cass Sunstein in a 2003 article in the American Economic Review. The authors further elaborated upon their ideas in a more in-depth article published in the University of Chicago Law Review that same year. They propose that libertarian paternalism is paternalism in the sense that "it tries to influence choices in a way that will make choosers better off, as judged by themselves" (p. 5); note and consider, the concept paternalism specifically requires a restriction of choice. It is libertarian in the sense that it aims to ensure that "people should be free to opt out of specified arrangements if they choose to do so" (p. 1161). The possibility to opt out is said to "preserve freedom of choice" (p. 1182). Thaler and Sunstein published Nudge, a book-length defense of this political doctrine, in 2008 (new edition 2009).

Libertarian paternalism is similar to asymmetric paternalism, which refers to policies designed to help people who behave irrationally and so are not advancing their own interests, while interfering only minimally with people who behave rationally. Such policies are also asymmetric in the sense that they should be acceptable both to those who believe that people behave rationally and to those who believe that people often behave irrationally.