The Koolhoven F.K.58 was a single engine, interceptor-fighter aircraft designed by Koolhoven under contract by France. Intended for Armée de l'Air use, the F.K.58 saw limited service in the Battle of France.
The F.K.58 was originally procured for use as colonial fighters. Instead, the 13 fighters operational by May 1940 were manned by expatriate Polish pilots of Captain Walerian Jasionkowski's improvised escadre, the patrouille DAT (Défense Aérienne du Territoire) based at Salon and Clermont-Aulnat. As delivered, the fighters were not armed and the Poles had to acquire machine guns and fit them. From 30 May 1940, they were used in the defence of French cities, patrolling in Avignon - Marseille area, then from Clermont-Ferrand, without any encounters with the enemy. The type's service life was short-lived with only 47 or so operational sorties recorded; the unit had no confirmed victories, but at least one F.K.58 was lost. After the fall of France, all surviving airframes were scrapped.