The University of Massachusetts Boston (UMass Boston) is a public US-based research university. It is the only public research university in Boston and the third-largest campus in the five-campus University of Massachusetts system.

The university is a member of the Coalition of Urban Serving Universities and the Coalition of Urban and Metropolitan Universities. It is classified among "R1: Doctoral Universities – Very high research spending and doctorate production".

The University of Massachusetts System dates back to the founding of Massachusetts Agricultural College under the Morrill Land-Grant Acts in 1863. Prior to the founding of UMass Boston, the Amherst campus was the only public, comprehensive university in the state. As late as the 1950s, Massachusetts ranked at or near the bottom in public funding per capita for higher education, and proposals to expand the University of Massachusetts into Boston was opposed both by faculty and administrators at the Amherst campus and by the private colleges and universities in Boston. In 1962, the 162nd Massachusetts General Court expanded the UMass System for the first time to Worcester, Massachusetts with the creation of the University of Massachusetts Medical School. In 1963, UMass President John W. Lederle informed the General Court that more than 1,200 graduates of Boston area high schools qualified to attend the University of Massachusetts were denied admission to the Amherst campus due to lack of space, and endorsed expanding the system with a commuter campus in Boston.

At the time, there were 12,000 freshman applications to the University of Massachusetts in Amherst with only 2,600 slots, yet the majority of the applicants lived in the Greater Boston area. In 1964, Massachusetts Senate Majority Leader Maurice A. Donahue and State Senator George V. Kenneally Jr. introduced a bill to establish a Boston campus for the UMass System. The bill was opposed by several private colleges and universities in the area, including Northeastern University, Boston University, and Boston College (who argued that the state would be better off subsidizing the existing private institutions in the city), as well as by Boston State College (who argued for expanding its campus on Huntington Avenue instead). However, the Huntington Avenue building of Boston State College could not be expanded to accommodate a 15,000-student campus, and the local news media and public opinion generally favored creating the new Boston campus for the UMass System.

In June 1964, with a $200,000 appropriation, the legislation establishing the University of Massachusetts Boston was signed into law. UMass President John W. Lederle began recruiting freshmen students, faculty, and administrative staff for the fall semester of 1965 (with goals of 1,000 students and 80 faculty members), and appointed his assistant at the Amherst campus, John W. Ryan, as UMass Boston's first chancellor. Ryan recruited tenured faculty members from the Amherst campus to relocate and form the UMass Boston faculty, and appointed Amherst's history professor Paul A. Gagnon and Amherst's provost and biology professor Arthur Gentile to hire the humanities and natural science faculty members respectively.

Serving as the new university's first provost, Gagnon became the most important faculty member in defining the curriculum and academic focus of the university, saying in June 1965 that "The first aim of the University of Massachusetts at Boston must be to build a university in the ancient tradition of Western civilization." Gagnon would be the principal architect of the university's brief attempt to create a Great Books program called the "Coordinated Freshman Year English-History Program", which was dismantled by the end of the 1960s.

Freshman classes started for 1,240 undergraduate students in September 1965 at a renovated building located at 100 Arlington Street in Downtown Boston, formerly the headquarters of the Boston Gas Company (which had leased the building to the university). Virtually the entire entering class were residents of Massachusetts, with the great majority living in the Greater Boston area. By the fall of 1968, the number of applications to UMass Boston for the fall semester had risen from 2,500 for fall 1965 to 5,700, and total enrollment had risen to 3,600. In the late 1960s, UMass Boston students on average were 23 years old, typically white and male, working part- or full-time, and either married or living with others in an apartment. UMass Boston also reportedly had the largest population of Vietnam War veterans of any US university and the largest population of African American students of all universities in Massachusetts.

In February 1966, the 164th Massachusetts General Court appropriated funds for the university to purchase the building at 100 Arlington Street. Over the next three years, the university also leased the Sawyer Building on Stuart Street, the Salada Buildings on Columbus Avenue, a part of the Boston Statler Hotel for faculty and departmental office space, and the Armory of the First Corps of Cadets (which was converted into the university's library). The student newspaper, The Mass Media, published its inaugural issue on November 16, 1966, and the Founding Day Convocation for the university was held December 10, 1966. In 1968, a group of students started the folk music radio station WUMB-FM. In the summer of 1968, inaugural Chancellor John W. Ryan resigned and was succeeded by historian Francis L. Broderick. Chancellor Broderick oversaw the reorganization of the university into separate colleges (College I and College II), along with the establishment of the College of Public and Community Service, and presided over the university's first graduation ceremony on June 12, 1969 (where 500 of the original 1,240 students received diplomas).