Allis may refer to:

People

• Charles David Allis (b. 1951), American biologist
• John Allis (b. 1942), American cyclist
• Louis Allis (1916-1994), American industrialist and Wisconsin Secretary of State
• Oswald T. Allis (1880-1973), American theologian
• William Allis (1901?1999), an American theoretical physicist specializing in electrical discharges in gases

Places

• Allis Township, Michigan
• North Allis Township, Michigan
• West Allis, Wisconsin

Other

• Allis-Chalmers, a former manufacturer of farm equipment based in Milwaukee, Wisconsin
• Big Allis, a giant generator in Queens, New York, commissioned by Consolidated Edison and built by Allis-Chalmers in 1965
• Allis-Chalmers Model B, popular tractor manufactured by Allis-Chalmers
• Charles Allis Art Museum, in Milwaukee, Wisconsin
• Allis shad, Alosa alosa, species of fish found in Europe and North Africa
• Fiat Allis, manufacturer of construction equipment