Alfonso `Fonsi` Gonzalez Nieto (born December 2, 1978 in Madrid, Spain). As the nephew of successful Grand Prix motorcycle road racer Ángel Nieto, it was no surprise when he started competing in the sport himself. After success in the 250cc class he moved to World Superbikes, while he also has made one MotoGP start.

He won the Spanish 125cc championship in 1998, and the Spanish 250cc champion in 1999 and 2000, also winning the less prestigious European 125cc title in 1997. In 1999 and 2000 he raced in the 250cc World Championship alongside his domestic commitments, finishing 14th overall on a Yamaha TZ250 with a best result of 6th at Estoril in 2000.

He was 4th in the world championship in 2001, with 4 successive 5th places early in the season and a pair of late-season podium finishes. He won 4 races in 2002, finishing 2nd to Marco Melandri. He was then 5th in 2003 with a win at Donington Park, and 7th in 2004.

In 2005 he entered the Superbike World Championship with the Caracchi Ducati team, finishing 17th overall in the championship. A fourth in round 4 of the season was the highlight; he only reached the top 10 once more. For 2006 and 2007 he rode for PSG-Kawasaki. His first podium finish came in race 2 at Assen in 2006, following team-mate Chris Walker`s victory in the first race. He was also third at Magny-Cours in 2007. He took pole position at Lausitzring in 2007 after finding a dry spell in a wet qualifying session.

In 2007 he also replaced the injured Olivier Jacque in the French Grand Prix making his debut in the MotoGP class.

For 2008 he joined Alstare Suzuki, making an immediate impact by winning his first world superbike race in the second race of the opening round in Qatar.