Christopher Michael Langan (born March 25, 1952) is an American horse rancher.
In 1999, as part of an interview Langan conducted with ABC's 20/20, a neuropsychologist administered an IQ test and remarked that Langan had the highest IQ score he'd encountered in 25 years.
Langan's IQ has been estimated by various sources to be between 195 and 210, and he has been described as "the smartest man in America" as well as "the smartest man in the world" by some journalists.Langan has developed what he calls a "theory of the relationship between mind and reality" which he calls the "Cognitive-Theoretic Model of the Universe" (CTMU).