The Heinkel He 112 is a German fighter aircraft designed by Walter and Siegfried Günter. It was one of four aircraft designed to compete for the 1933 fighter contract of the Luftwaffe, in which it came second behind the Messerschmitt Bf 109. Small numbers were used for a short time by the Luftwaffe and some were built for other countries, with around 100 being completed.

Siegfried Günter and Walter Günter were German twin brothers and pioneering aircraft designers. Walter was responsible for the world's first rocket-powered and turbojet airframes, projects funded by Nazi Germany. Siegfried was the father of the "thrust modulation theory".