John Appleton (July 12, 1804 – February 7, 1891) was a prominent American legal reformer, jurist, and scholar in the fields of constitutional economics and classical liberalism. Appleton is known for his jurisprudence in rules of evidence and individual rights, and was one of the first proponents of laissez-faire constitutionalism, decades before the doctrine was mainstreamed across the United States under the Lochner Court. Appleton corresponded regularly with famous British philosopher John Stuart Mill and was considered very influential on his work.