Willem "Wim" de Graaff (born August 25, 1931) is a Dutch former speed skater who competed in the 1956 Winter Olympics and in the 1960 Winter Olympics.
He was born in Rotterdam.
In 1956 he finished fourth in the 5000 metres event, eleventh in the 1500 metres competition, 18th in the 10000 metres contest, and 43rd in the 500 metres event.
Four years later he finished 15th in the 1500 metres competition and 28th in the 500 metres contest at the 1960 Games.