The number of Division I schools sponsoring men's volleyball has fluctuated between 20 and 24 teams since 1986. No traditional D-I conferences sponsored men's volleyball until the Big West Conference added the sport for the 2018 season. The Big West became the first NCAA men's volleyball league to consist entirely of D-I members when UC San Diego, which was one of the six charter members of Big West men's volleyball, began a transition to D-I upon joining the Big West full-time in July 2020. Of the other three major conferences, the Eastern Intercollegiate Volleyball Association (EIVA) and Midwestern Intercollegiate Volleyball Association (MIVA) are volleyball-specific conferences, while the Mountain Pacific Sports Federation (MPSF) is a multi-sport conference of schools whose primary conferences do not sponsor its ten sports. In addition to the 24 D-I schools, 31 Division II schools will compete in D-I volleyball during the 2021 season (subject to COVID-19 disruptions):