Roy Edward Oswalt (pronounced /ˈoʊzwɑːlt/) (born August 29, 1977 in Weir, Mississippi) is an American Major League Baseball player who debuted on May 6, 2001. Oswalt, a slender six-foot zero-inch right-handed starting pitcher, is currently in his ninth major league season. He has spent his entire career in the Houston Astros organization.

Oswalt is the major league leader in wins since he was called up in 2001.

Oswalt grew up in Weir, Mississippi, the son of Billy Oswalt, a logger and a Vietnam veteran. He is married to his high school sweetheart, Nicole, and together they have two daughters. When they were kids, he and Nicole used to play T-ball against one another. At Weir High School, Oswalt played defensive back and wide receiver on the football team, who won a state title his senior year. He graduated in a class with 32 students.