Jason Marquis, American baseball player
Jason Scott Marquis (; born August 21, 1978) is an American former professional baseball pitcher. He played in Major League Baseball (MLB) for the Atlanta Braves, St. Louis Cardinals, Chicago Cubs, Colorado Rockies, Washington Nationals, Arizona Diamondbacks, San Diego Padres, Minnesota Twins, and Cincinnati Reds. He also is notable for playing for Israel at the 2017 World Baseball Classic, serving as the team's ace.

As a 12-year-old, Marquis pitched his team to third place in the Little League World Series with a no-hitter. He is one of only a few ballplayers to have played in both a Little League World Series and a Major League World Series. He also pitched his high school team to consecutive New York City baseball championships. Marquis was drafted in the first round out of high school by the world champion Atlanta Braves, and reached the majors as a 21-year-old in 2000.

As a major leaguer, Marquis won 11 or more games for six straight years through 2009, and also started 28 or more games in each of the years 2004–09. His 65 wins from 2004 to 2008 ranked 7th among N.L. pitchers. He pitched on a World Series champion in 2006, and was an All-Star in 2009. Through 2011, in his career in games that were late and close, Marquis held batters to a .228 batting average. He also excelled with the bat, winning the Silver Slugger Award in 2005. He pitched for Team Israel at the 2017 World Baseball Classic. In February 2017, Marquis, who had not filed retirement papers, said he was interested in pitching in professional baseball again.