The Massachusetts Interscholastic Athletic Association (MIAA) is an organization that sponsors activities in thirty-three sports, comprising 374 public and private high schools in the U.S. state of Massachusetts. The MIAA is a member of the National Federation of State High School Associations (NFHS), which writes the rules for most U.S. high school sports and activities. The MIAA was founded in 1978, and was preceded by both the Massachusetts Secondary School Principals Association (MSSPA) (1942–1978) and the Massachusetts Interscholastic Athletic Council (MIAC) (1950–1978).