John Madsen may refer to:
John Madsen (American football) (born 1983), American football player John Madsen (footballer) (born 1937), Danish association football player John Madsen (physicist) (1879–1969), Australian academic, physicist, engineer and mathematician John M. Madsen (born 1939), American leader in The Church of Jesus Christ of Latter-day Saints
See also Jon Madsen (born 1980), American MMA fighter