The following lists Missouri high schools and the athletic conferences in which they compete. Under the current system used by the Missouri State High School Activities Association some conference member teams may also compete in the same playoff district while others are in districts with non-conference members. As a general rule most conferences contain schools within their region and of similar class size, the class based on school enrollment. There are also some smaller, sport specific conferences in Missouri such as the Quad County and West Central for football but the ones listed are majority the primary conferences for all sports.
Disbanded in 2022.
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The Kansas members of the conference withdrew to form a new league within the Kansas State High School Activities Association.
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Two former members, Heritage Christian Academy (Olathe, KS) and Cair Paravel Latin (Topeka, KS) are now full members of the Kansas State High School Activities Association.
This League appears to be defunct.
Carrollton and Richmond have been conference members since its founding in 1928. Lexington joined in 1934 and Lafayette County (Higginsville) in 1937. <nowiki> </nowiki>
Grain Valley left the conference at the end of the 2017-18 school year and joined the Suburban Kansas City Conference. Warrensburg replaced Grain Valley.
Center and Clinton were added beginning in the 2020-21 school year.
Excelsior Springs departed after the 2021-22 school year and followed Grain Valley to the Suburban Kansas City Conference. <nowiki> </nowiki>
The conference is set to dissolve following the 2025-26 school year.
St. Louis Public Schools Only
Football Only Conference
The following lists schools that are independents, meaning they do not belong to or compete in any of the athletic conferences above. However they do compete against other schools in Missouri (and sometimes surrounding states) on a non-conference basis. Independents are included in the MSHSAA playoff system based on a District assignment separate from any athletic conference.
Departing members are in red.