William (Willy) Ostijn, also seen as Ostyn (13 July 1913 in Kachtem – 30 March 1993 in Roeselare), was a classical Belgian composer of the 20th century.At the age of sixteen, Willy Ostijn entered the Lemmensinstituut of Malines to study the piano with Marinus de Jong and the organ with Flor Peeters. He got a pedagogical diploma at the Royal Conservatory of Ghent, and first prizes of counterpoint, piano, chamber music and composition. Willy Ostijn becomes the second organist of the St Rumoldus’ Cathedral of Malines. From 1938 until his retirement, he was also a professor of musical education at the Royal Atheneum of Roeselare, a function that did not prevent him from giving lectures at the Music Academy of Izegem from 1939 to 1949.Before the Second World War, Ostijn had a reputation with the Trio Willy Ostijn which played the great works of the repertory and Ostijn’s own compositions.