Delio Onnis (born 24 March 1948) is a former professional football player who played as striker.

[1][2][4] Onnis was born in Giuliano di Roma in Italy, but moved to Argentina before he was 3 and subsequently gained Argentinian citizenship.

[4] In 1974, the newly promoted Monaco signed him and over the next seven seasons he was their top scorer every year, eventually scoring 223 goals, with 157 in the league.

[1][2][4] Onnis was never called up for Argentina which had a policy of favouring players who remained in the domestic league, and throughout the 70s and 80s he, like Carlos Bianchi, was behind compatriots such as Mario Kempes and Leopoldo Luque in the Argentinian pecking order.

Following Bianchi's return to Argentina in 1980, Onnis went on to win four back-to-back scoring titles of his own, leaving them with five apiece and meaning that in eleven seasons between 1973–74 and 1983–84 they won five scoring titles each with only Vahid Halilhodžić's win in 1982 for Nantes breaking their dominance.