Gaston Étienne Ghislaine Reiff (24 February 1921 – 6 May 1992) was a Belgian runner.

He competed at the 1948 and 1952 Olympics in the 5000 m event and won it in 1948, defeating Emil Zátopek in the final and becoming the first Belgian track and field athlete to win an Olympic title.

[2] Reiff competed in boxing and football before changing to athletics.

Besides his Olympic gold medal he set world records in the 2000 m, 3000 m and 2 miles and won 24 national titles; in 1951 he held Belgian records on distances ranging from 1000 m to 10000 m. A street in Braine-l'Alleud and the town's stadium are named after Reiff in his home town of Braine-l'Alleud.

This biographical article relating to Belgian athletics is a stub.