The 1915 World Series was the championship series in Major League Baseball for the 1915 season. The 12th edition of the World Series, it matched the American League champion Boston Red Sox against the National League champion Philadelphia Phillies. The Red Sox won the Series four games to one. It was the last World Series to start on a Friday until the 2022 World Series.

The Boston Red Sox are an American professional baseball team based in Boston. The Red Sox compete in Major League Baseball (MLB) as a member club of the American League (AL) East Division. Founded in 1901 as one of the American League's eight charter franchises, the team's home ballpark has been Fenway Park since 1912. The "Red Sox" name was chosen by the team owner, John I. Taylor, c. 1908, following the lead of previous teams that had been known as the "Boston Red Stockings", including the Boston Braves. The team has won nine World Series championships, tied for the third-most of any MLB team, and has played in 13 World Series. Their most recent World Series appearance and win was in 2018. In addition, they won the 1904 American League pennant, but were not able to defend their 1903 World Series championship when the New York Giants refused to participate in the 1904 World Series.