An Unreasonable Man is a 2006 documentary film that traces the life and career of political activist Ralph Nader, the founder of modern consumer protection in America and perennial presidential candidate. Contrary to the title's apparent message, the film was actually created to defend Nader and restore his reputation after his controversial role in the 2000 U.S. presidential election.

Besides featuring Mr. Nader himself, the film presents interviews with current and former members of Nader's Raiders, including Joan Claybrook and Robert Fellmeth, as well as political commentators such as Phil Donahue, Pat Buchanan, and Eric Alterman. The film takes its name from the George Bernard Shaw quotation, "The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man."