The Heinkel He 112 was a fighter aircraft designed by Walter and Siegfried Günter. It was one of four aircraft designed to compete for the Luftwaffe's 1933 fighter contract, which was eventually won by the Messerschmitt Bf 109. Small numbers were used for a short time by the Luftwaffe, and small runs were completed for several other countries, but less than 100 were completed in total. It remains one of the least known production fighter designs.