Ricardo Izecson dos Santos Leite (Portuguese pronunciation: [ʁiˈkaɾdu iˈzɛksõw duˈsɐ̃tus ˈlejt͡ʃi]; born 22 April 1982), commonly known as Kaká (Portuguese: [kaˈka] ( listen)) or Ricardo Kaká, is a Brazilian professional footballer who last played as an attacking midfielder for Orlando City and the Brazil national team.

Kaká made his professional debut at age 18 at São Paulo FC in 2001. In 2003, he joined Italian club Milan for a fee of €8.5 million, after being named to the Bola de Ouro as the best player in the 2002 Campeonato Brasileiro. While at Milan, Kaká won a Serie A title and was named the Serie A Footballer of the Year two times. In the 2004–05 season, the squad reached the 2005 UEFA Champions League Final, where they lost to Liverpool on penalty shoot-outs, and Kaká was the top assist provider of the tournament, being named the UEFA Club Midfielder of the Year. Two years later, he led Milan to win the 2006–07 UEFA Champions League, being the tournament's top scorer. After the season, he won the FIFA World Player of the Year, the Ballon d'Or, the UEFA Club Footballer of the Year and the IFFHS World's Best Playmaker awards.

After his success with Milan, Kaká joined Real Madrid for a transfer fee of €67 million. At the time, this was the second highest transfer fee (in euros) ever, behind only the €77.5 million (150 billion lire) fee for Zinedine Zidane. However, in the same window Real Madrid broke the world record by signing Cristiano Ronaldo. After four seasons in Spain, he returned to Milan for a season in 2013, scoring his 100th goal for the club. At the end of the 2013–14 season, he joined MLS expansion club Orlando City, but initially returned to his former Brazilian club São Paulo FC on loan. In 2015, he scored on his MLS debut for Orlando City; he was later included in the roster for the 2015 MLS All-Star Game, where he was named Most Valuable Player.

At international level, Kaká made his debut for the Brazil national team in 2002, and was selected for their victorious World Cup squad that year, as well as the 2006 and 2010 tournaments, leading the tournament in assists in the latter. He was also a member of Brazil's 2005 and 2009 FIFA Confederations Cup-winning squads, winning the Golden Ball Award in the 2009 edition, as the tournament's best player.

Kaká is widely considered one of the best players of his generation. He was nominated three times to both the FIFPro World XI and the UEFA Team of the Year. In 2010, he was named to the A.C. Milan Hall of Fame. In 2017, ESPN ranked Kaká eighteenth on its list of the world's most famous athletes. He was the first sportsperson to amass 10 million followers on Twitter. He is one of four players, alongside Ronaldinho, Rivaldo and Zinedine Zidane, to have won the FIFA World Cup, the UEFA Champions League title and the Ballon d'Or.

In addition to his contributions on the pitch, Kaká is known for his humanitarian work. In 2004, by the time of his appointment, he became the youngest ambassador of the UN World Food Programme. For his contributions on and off the pitch, Kaká was named in the Time 100 list of the world's most influential people in 2008 and 2009.