The MHSAA is a member of the National Federation of State High School Associations (NFHS).

The activities which the MHSAA oversees include chess, esports, debate, drama, speech, writing-prose, poetry, short stories, essays and music, both band and choral.

The athletic competitions of which the MHSAA oversees include archery, football, swimming, slowpitch softball, volleyball, cross country, soccer, basketball, powerlifting, tennis, golf, track, baseball and fastpitch softball.

[1] On April 7, 2022, it was announced that the MHSAA will add a 7th classification starting for the 2023-24 school year and will be based on student numbers for grades 9-11.

Under the new system, the top 24 schools in terms of enrollment as per the Mississippi Department of Education are in the new 7A classification.