Collegiate summer baseball leagues are amateur baseball leagues in the United States and Canada featuring players who have attended at least one year of college and have at least one year of athletic eligibility remaining. Generally, they operate from early June to early August. In contrast to college baseball, which allow aluminum or other composite baseball bats, players in these leagues use only wooden bats, hence the common nickname of these leagues as "wood-bat leagues". Collegiate summer leagues allow college baseball players the ability to compete using professional rules and equipment, giving them experience and allowing professional scouts the opportunity to observe players under such conditions.

Amateur baseball is baseball in which the players either are not paid for playing, or receive only a modest stipend or employment arranged by the team's boosters. Amateur baseball is played in the United States by players of all ages, from young children to adults.