Geldermalsen is a town and former municipality in the province of Gelderland in the Netherlands.

Gelderland, also known as Guelders in English, is a province of the Netherlands, occupying the centre-east of the country. With a total area of 5,136 km2 (1,983 sq mi) of which 176 km2 (68 sq mi) is water, it is the largest province of the Netherlands by land area, and second by total area. Gelderland shares borders with six other provinces and the German state of North Rhine-Westphalia.