The Fokker S.IV was a military trainer aircraft produced in the Netherlands in the mid-1920s. It was a conventional, single-bay biplane with staggered wings of unequal span braced with N-struts, essentially a radial-engined development of the S.III. The pilot and instructor sat in tandem, open cockpits and the undercarriage was of fixed, tailskid type with a cross-axle between the main units. The Royal Netherlands Army Aviation Group purchased 30 examples and used them right up to the German invasion of the Netherlands in 1940.