Eugène Allonsius
 Eugène Allonsius (born 12 December 1937) is a retired Belgian middle- and long-distance runner. He competed at the 1960 and 1964 Summer Olympics in the 1500 metres and 5000 metres events but failed to reach the finals.During his career Allonsius set five national records. He was a two-time Belgian champion in the 1500 m won the 5000 m national title at nine times and was also the 1968 national champion in the 10000 metres.