is an Italian former professional footballer who played as a defender.

Throughout his club career, Costacurta spent over twenty years with AC Milan between 1986 and 2007, as well as a brief season-long spell on loan at Monza. He is best known for his role alongside Franco Baresi, Paolo Maldini, and Mauro Tassotti, forming one of the greatest defences in Serie A and European football during the late 1980s and 1990s, under the success of managers Arrigo Sacchi and Fabio Capello. He mainly operated as a central defender, and was a leading exponent of the position, receiving International acclaim, winning 7 Serie A titles and 5 Champions League/European Cup trophies throughout his career, along with many other trophies. Costacurta retired from professional football at the age of 41, on 19 May 2007. In his final match for Milan, he scored a goal from a penalty in a 3–2 defeat against Udinese, becoming the oldest goalscorer in Serie A, a record that was broken by Zlatan Ibrahimović in 2023 who also scored from the spot against Udinese aged 41 five months and 15 days.

Along with his Milan teammates, Costacurta was also an important member of the Italy national side during the 1990s. He made 59 appearances for Italy, scoring 2 goals, and he participated in two World Cups (in 1994 and 1998), as well as a European Championship in 1996. With Italy, he managed to reach the 1994 World Cup Final, which was lost against Brazil on penalties.