The Rearwin Sportster is a 1930s American two-seat, high-winged, cabin monoplane designed and built by Rearwin Aircraft & Engines for sport/touring use.

Rearwin Airplanes was a series of US airplane-manufacturing businesses founded by Andrew ("Rae") Rearwin in 1928. Rae Rearwin was an American businessman who had developed several successful business ventures in the Salina, Kansas area in the early 20th century. Although he had no experience with aircraft manufacturing, he felt that he could succeed with his solid business acumen. With his two sons, Ken and Royce, he hired some engineers and built the Ken-Royce in a garage in Salina. The business moved to the Fairfax Airport in Kansas City, Kansas, and went through several variations before it was sold to Commonwealth Aircraft in 1942, which went bankrupt in 1946.