De Coster or Decoster is a Dutch occupational surname, most common in Flanders. Coster is an archaic spelling of modern Dutch "koster" (parish clerk). People with this surname include:
Adam de Coster (c. 1586–1643), Flemish Baroque painterCharles De Coster (1827–1879), Belgian novelist best known for his Legend of Thyl UlenspiegelDominicus de Coster (c. 1560–1612), Flemish artist, printer and copperplate engraverJean-Baptiste De Coster (guide) (1760–1826), an unwilling Flemish guide for Napoleon at WaterlooJean-Baptiste De Coster (Jesuit) (1896–1968), a Belgian priest who sheltered Jews from the HolocaustJonathan Decoster (born 1987), American football playerKoen Decoster, Belgian historian, philosopher and translatorMaggy de Coster (born 1966), French writerRoger De Coster (born 1944), Belgian motocross racer and team managerSaskia De Coster (born 1976), Belgian writer