Gaël Sébastien Monfils (French pronunciation: ) (born 1 September 1986) is a French professional tennis player. As of 2011 he was the highest-ranked French tennis player, ranked 7th in the world ATP rankings. He was the runner-up at the Paris Masters in 2009 and 2010 and a semi-finalist at the 2008 French Open.
In 2002, Monfils finished as 24th at the Dutch Junior Open. In the same year, he won the German Junior Open (defeating Bayer). Monfils ended the year ranked the 4th junior in the world. He also represented France in the junior Davis Cup.
Monfils got off to a positive start in 2003 as earned his first career ATP point at the France Futures No.13 by reaching the second round. He also reached the second round at France #14, Egypt #2, and Spain #28. In that year, he played a total of nine Futures events. This included a showing in the doubles final at Spain #27. In junior events, he was the runner-up at Orange Bowl (losing to Marcos Baghdatis) and USTA International Winter Championships (losing to Sebastian Rieschick). He reached the quarter-final of the Australian Open juniors tournament (losing to Florin Mergea) and won the doubles title at the Victorian Junior Championships (with Josselin Ouanna). He was number 21 in junior rankings at the end of the year.