is an Italian former professional footballer who played as a centre-back. He was selected to the Serie A Team of the Year four times.

After playing for several smaller Italian clubs in the lower divisions of Italian football in his early career, he made his Serie A debut with Chievo in 2003, and eventually came to prominence while playing for Palermo. In 2008, he was signed by German side VfL Wolfsburg, where he remained for two and a half seasons, winning a Bundesliga title in 2009. In 2011, he returned to Italy, joining Juventus, where he later won eight consecutive Serie A titles between 2012 and 2019, among other trophies, including a record of four consecutive Coppa Italia titles between 2015 and 2018; having also played two UEFA Champions League finals between 2015 and 2017.

At international level, he represented the Italy national football team on 73 occasions between 2004 and 2017, taking part at the 2004 Summer Olympic Games where he obtained a bronze medal, at two FIFA World Cups (2006 and 2014), three UEFA European Championships (2008, 2012, and 2016), and at the 2013 FIFA Confederations Cup, where himself and the team also won bronze. He was most notably a member of the Italian 2006 World Cup winning squad, as well as a starting member of the Italian squad that reached the UEFA Euro 2012 final.