The Allis-Chalmers Model C was a small row-crop tractor manufactured by Allis-Chalmers from 1940 to 1949. It was developed from the smaller Allis-Chalmers Model B.

The Model B was too small to work two crop rows at once. Allis-Chalmers briefly adapted the Allis-Chalmers Model WC as the RC from 1938 to 1941, but it proved expensive, so the B was adapted with wider wheel spacing options, a larger engine, and additional fuel options. The Model C used the RC's 125-cubic-inch (2,050 cc) Allis-Chalmers 4-cylinder engine, with gasoline and distillate fuel options. The C inherited the B's three-speed transmission, power take-off and hydraulics.^[1][2][3][4]

84,020 Model Cs were built at the Allis-Chalmers plant in West Allis, Wisconsin. In 1949 a Model C sold for about $1,200.^[3]

Starting in 1949, the Model C was replaced by the Model CA, with greater power, allowing it to be rated as a two-plow tractor. The engine remained the same, but turned at a higher RPM and had a higher degree or compression, yielding 11 percent more power. It was provided with a new four-speed transmission, and power assist rear wheel adjustment was introduced. The CA was produced with single and narrow dual wheel front ends, and an adjustable wide front axle.^[5][6][4]

39,499 CAs were produced at West Allis until 1958, with a 1958 price of about $1,900.^[6]