Jayson Richard Werth (born May 20, 1979, in Springfield, Illinois) is an outfielder in Major League Baseball who currently plays for the Philadelphia Phillies. He was mainly a bench player with Toronto and Los Angeles, but became a starter in 2007 after an injury to Shane Victorino.

Werth comes from an athletic family. His sister, Hannah, is a volleyball player for the University of Nebraska. He is the son of Jeffrey J. Gowan (who led all Division I wide receivers in receptions while playing football for Illinois State University in 1976, and played in the St. Louis Cardinals minor league affiliate, the Johnson City Cardinals in 1978) and Kim Schofield Werth, who competed in the U.S. Olympic Trials in the long jump and 100 meters. He is also the grandson of Ducky Schofield and nephew of Dick Schofield, both Major League Baseball infielders, and stepson of Dennis Werth, who played in parts of four seasons with the Kansas City Royals and New York Yankees from 1979-1982. Werth is married, with two children.

Werth's baseball talents blossomed at a young age. He teamed up with three other pitchers to combine for a no-hitter in a 56–1 victory en route to a 3rd place finish at Nationals. He first gained attention while attending Glenwood High School in Chatham, Illinois, where he compiled a .652 batting average in his senior year with 15 home runs in 31 games. He initially planned on playing college ball at the University of Georgia, but abandoned that plan when he was drafted in the first round by Major League Baseball's Baltimore Orioles on June 13, 1997. Prior to making his major league debut, the Orioles traded Werth to the Toronto Blue Jays for pitcher John Bale. Werth broke into the major leagues with the Toronto Blue Jays in 2002.