​John Alton A.S.C. (October 5, 1901 – June 2, 1996), born Johann Altmann, in Sopron/Ödenburg, Kingdom of Hungary, Austria-Hungary, was an American cinematographer. Alton won an Academy Award for the cinematography of An American in Paris (1951), becoming the first Hungarian-born person to do so. He photographed some of the most famous film noirs of the classic period. He started out in Los Angeles as a lab technician in the 1920s, later becoming a cameraman within four years. He moved to France with Ernst Lubitsch to film backgrounds for The Student Prince in Old Heidelberg (1927) and ended up staying for one year heading the camera department of Paramount Pictures's Joinville Studios. In 1932 he moved to Argentina where he shot many Spanish-language films and designed the country's first sound film studio for Lumiton and Argentina Sono Film.

He returned to Hollywood in the late 1930s, with two dozen film credits, and became one of the most sought after cinematographers in American cinema.

Alton was known for unconventional camera angles—especially low camera shots. His style is most notable in the film noirs: He Walked by Night, The Big Combo, The Amazing Mr. X, T-Men, and Raw Deal.

Alton also photographed many color movies including Slightly Scarlet (a color film noir).