Stephen J. Flesch (born May 23, 1967) is an American professional golfer, competing on the PGA Tour.

Flesch was born in Cincinnati, Ohio, and attended Covington Catholic High School in Park Hills, Kentucky. After graduation he played golf at the University of Kentucky and turned professional in 1990.

Flesch finished in the top ten on the Asian Tour Order of Merit in 1993, 1994 and 1996. He won the 1997 NIKE Tour Championship to earn a PGA Tour card for the following season, only the second left-hander to win on what is now the Web.com Tour. His first win on the PGA Tour was the 2003 HP Classic of New Orleans, but is probably best known for his come-from-behind victory at the 2004 Bank of America Colonial in Fort Worth, Texas. He has been featured in the top 50 of the Official World Golf Rankings, reaching a career high of 24th in 2004.

Entering the 2008 Masters Tournament, Flesch was ranked number 107 in the world rankings. After three rounds, he was in third place at eight-under, three strokes behind leader and eventual champion Trevor Immelman. Playing in the penultimate pairing on breezy Sunday, Flesch posted a 78 to finish six strokes back, tied for fifth. This strong showing in a major tournament strengthened his world ranking by 28 slots, improving it to number 79.

Flesch last played a full season in 2011, then missed the cut in the 12 events he played during the 2012 season. In 2015, he finished T7 at the Barracuda Championship, his first top ten in four years.