Stephen James Strasburg (/ˈstrɑːsbɜːrɡ/; born July 20, 1988) is an American former professional baseball pitcher who is currently an assistant with the San Diego State Aztecs baseball program. He spent his entire 13-year Major League Baseball (MLB) career with the Washington Nationals. He is a three-time All-Star and the World Series MVP of the Nationals team that won the 2019 World Series.

A talented but unpolished high school baseball player at West Hills High School, Strasburg played college baseball for the San Diego State Aztecs. There, he became one of the best collegiate pitchers in the country. Strasburg pitched for the United States national baseball team at the 2008 Summer Olympics, winning the bronze medal. Two years later, he was called the "most-hyped pick in draft history" by ESPN and the "most hyped and closely watched pitching prospect in the history of baseball" by Sports Illustrated.

Strasburg was selected by Washington with the first overall pick in the 2009 MLB draft. He recorded a franchise-record 14 strikeouts in his major league debut in June 2010. In his 12th major league game, Strasburg tore a ligament in his pitching elbow. The injury required Tommy John surgery and a year of rehabilitation. He rejoined the Nationals in September 2011, but was only able to pitch 24 innings that year. Strasburg's 2012 season marked a successful return to form; he was selected to play in the 2012 MLB All-Star Game. After he pitched 28 games in the 2012 season, the Nationals decided to shut him down for the rest of the year out to avoid overworking him in his first year after surgery. The move was highly controversial and was the subject of much debate, especially since the Nationals made the playoffs for the first time in 2012 but were eliminated in the first round.

Strasburg established himself as one of the premier pitchers in the game, though he was placed on the disabled list due to injuries several times. He led the National League (NL) in strikeouts in 2014. During the 2016 season, he signed a seven-year contract extension to remain with the Nationals, and was an All-Star that year and the following year. He led the NL in wins in 2019 with 18. Strasburg received the 2019 World Series Most Valuable Player Award for starting and winning two games against the Houston Astros as the Nationals won their first championship.

Following the Nationals' 2019 World Series victory, Strasburg opted out of his contract and then re-signed with the Nationals on a larger seven-year, $245 million deal, which was to run through 2026. Strasburg pitched only 311⁄3 innings for the Nationals after signing that contract, making his final appearance in 2022. After repeated attempts to repair damage from thoracic outlet syndrome failed, Strasburg officially retired in 2024.

Strasburg was born in San Diego, California, to Jim Strasburg, a real estate developer, and Kathleen Swett Strasburg, a dietician. He grew up a San Diego Padres fan.

Strasburg credits his maternal grandmother with helping him develop his baseball skills as a child. She would frequently play catch and even work on pitching with him. He labels her as one of his biggest inspirations.

Strasburg attended West Hills High School in Santee, California. At first, he struggled on the school's baseball team, posting a 1–10 win–loss record in his junior year. A 12-strikeout game against El Capitan High School in his senior year, in which Strasburg allowed just one hit, drew attention from scouts. He finished his senior year with a 1.68 earned run average (ERA) and 74 strikeouts in 62+1⁄3 innings pitched, with seven complete games. He finished with three varsity letters, set school records in ERA and shutouts, and was named his school's 2006 Scholar-Athlete of the Year. He was also named second-team all-league and his team's MVP. Despite these achievements, he was not selected in that year's Major League Baseball draft.