The ECAC men's basketball tournaments are postseason college basketball tournaments organized by the Eastern College Athletic Conference (ECAC).

Despite its name, the ECAC is not a traditional athletic conference, but rather a loosely organized sports federation for colleges and universities in the northeastern United States. Among other things, it organizes end-of-season college basketball tournaments for member schools which are not members of a traditional conference, or which do not otherwise have access to such a tournament. At various times, it has organized end-of-season basketball tournaments at the National Collegiate Athletic Association (NCAA) Division I, Division II, and Division III levels.

From 1975 to 1982, the ECAC organized annual regional end-of-season men's basketball tournaments for independent Division I ECAC member colleges and universities in the Northeastern United States. The winner of each regional tournament was declared the ECAC regional champion for the season and received an automatic bid in the NCAA Division I men's basketball tournament.^[1]

Before 1975, the ECAC had not organized such tournaments for Division I schools; the NCAA tournament invited only one team per Division I conference and accommodated independents with a limited number of at-large bids. In 1975, however, the NCAA tournament's field expanded to 32 teams, including the champions of end-of-season conference tournaments, who received automatic bids. Although a number of at-large bids still existed, the process for selecting the field for the 1975 NCAA tournament included many second-place conference teams and threatened to exclude independent schools in the northeastern United States, which had no end-of-season conference tournament to play in and therefore no automatic bids. With no conventional athletic conferences yet in existence in the Northeast, the ECAC began to organize its Division I basketball tournaments in 1975, allowing Northeastern independents to retain their independent status while still having an opportunity to play in an end-of-season tournament offering an automatic bid. The ECAC Division I tournaments thus assured that at least some Northeastern colleges and universities would receive NCAA tournament bids.^[2][3]

In both 1975 and 1976, the ECAC organized four regional Division I tournaments: Metro (for the New York City area and New Jersey); New England; South (for Pennsylvania, Maryland, Virginia, West Virginia, and Washington, D.C.); and Upstate (for Upstate New York). As Eastern independent colleges and universities began to join existing conferences or form new ones and play in their own end-of-season conference tournaments, the number of ECAC regional tournaments declined due to reduced demand for them. After the formation of the Eastern Collegiate Basketball League (which later became the Atlantic 10 Conference), the ECAC combined its Southern and Upstate Regions into a single "Southern" (later "Upstate-Southern" and "South-Upstate") Region and held only three regional tournaments in 1977, 1978, and 1979. After the teams that played in the New England region all joined the Big East Conference, the Atlantic 10 Conference, or the new ECAC North Conference (which later became the America East Conference), the ECAC also did away with its New England tournament, and in 1980 and 1981 it held only two tournaments, Metro and Southern. Many of the teams in the Metro Region then formed the Metro Atlantic Athletic Conference (MAAC), and in 1982 the ECAC held two tournaments, reorganized as the Metro-South (composed of former Metro Region teams which had not joined the MAAC) and South tournaments.^{[2][3][4][5][6]}

After the completion of the 1982 post-season, the remaining ECAC Metro-South Region teams formed the ECAC-Metro Conference (which later became the Northeast Conference), while the ECAC South Region teams formed the ECAC South Conference (which later became the Colonial Athletic Association). With all the former independents in the northeastern United States having joined a traditional conference holding its own end-of-season tournament, and with the National Invitation Tournament providing a means of postseason tournament play for Division I teams not invited to the NCAA tournament, the ECAC had no reason to continue its Division I basketball tournament series, and it ceased to organize such tournaments after 1982.^[7]