De Schelde S.21

S.21
Role Fighter aircraft
National origin Netherlands
Manufacturer NV Koninklijke Maatschappij De Schelde
Status Project abandoned
Number built 1 incomplete prototype

The De Schelde S.21 was a proposed Dutch fighter of the late 1930s and early 1940s. It was a single-seat, single-engined, pusher monoplane. A single prototype was under construction in 1940, but work was abandoned due to the German invasion.