The 1918 Chicago Cubs season was the 47th season of the Chicago Cubs franchise, the 43rd in the National League and the third at Wrigley Field. The Cubs finished first in the National League with a record of 84–45, 10.5 games ahead of the second place New York Giants. The team was defeated four games to two by the Boston Red Sox in the 1918 World Series.

The 1918 New York Giants season was the franchise's 36th season. The team finished in second place in the National League with a 71–53 record, 10½ games behind the Chicago Cubs.