Antônio Reginaldo Pizzonia Júnior (born September 11, 1980 in Manaus) is a Brazilian racing driver who has raced in Formula One and the Champ Car World Series.

He is nicknamed "Jungle Boy", a reference to his native Amazonas. He is currently a resident of Manaus, a city in the northern part of Brazil and capital of Amazonas State.

From 1991 to 1996 he competed in various karting series. In 1997 he moved to Britain and competed in Formula Vauxhall Junior; Pizzonia placed second, and won the Winter Festival. In 1998, in addition to taking the Championship in F-Vauxhall Junior, he won the Formula Renault Winter Festival. His 1999 season was even more successful, winning the British F-Renault series and finishing second in its European counterpart. In 2000, Pizzonia took 5 wins on his way to winning the British Formula Three Championship.

For 2001, Pizzonia switched to the Formula 3000 series, winning one race and finishing sixth in the championship.

In 2002, Pizzonia was hired as test driver for Williams, but also continued in F3000, placing 8th. After impressive testing performances, he was signed by the Jaguar team to partner Mark Webber for 2003. However, following a string of poor results, he was dropped midway through the season and replaced by Minardi's Justin Wilson.