The Missouri State High School Activities Association is the organization that oversees high school activities for the state. It promotes participation, sportsmanship and team play among its members. As of 2015, the MSHSAA's membership includes 580 high schools.
The MSHSAA coordinates game dates and standardizes eligibility requirements for sports such as basketball, tennis, softball and water polo. It also oversees activities such as bass fishing, chess, music and scholar bowl. The MSHSAA was established in 1926 and organizes schools based on enrollment, with the smallest identified as Class 1. Every two years, the schools are regrouped as enrollments change. The organization is headquartered in Columbia, Missouri, as of 2015.