Antônio Reginaldo Pizzonia Júnior (born 11 September 1980) is a Brazilian professional racing driver who has raced in Formula One and the Champ Car World Series. As of 2013, he is competing in the FIA World Endurance Championship (driving for Delta-ADR) and the Grand-Am Rolex Series (driving for Michael Shank Racing).
Born in Manaus, Pizzonia started his car racing career in the Formula Vauxhall Junior series in 1997, and then progressed through various junior formulae, winning the Formula Vauxhall Junior Winter Festival in 1997, the Formula Vauxhall Junior and Formula Renault Winter Festival in 1998, the Formula Renault 2.0 UK in 1999, and the British Formula 3 Championship in 2000. For 2001 and 2002, he entered the Formula 3000, with his best championship finish being sixth in 2001. In 2003, he was signed by the Jaguar Formula One team, but following poor results, was released during the season. In 2004, he replaced the injured Ralf Schumacher at Williams in several events, securing his first Formula One points in the process. In 2005, he replaced Nick Heidfeld at Williams, but was released from his contract at the end of the season. Since then, he has competed in multiple series, such as the Champ Car World Series, the Superleague Formula, Stock Car Brasil, and the FIA GT1 World Championship.