[10] Its budget was large enough that several distinguished gentlemen taught at Roxbury Latin early in their careers, including future Supreme Court justice William Cushing and Massachusetts governor Increase Sumner.

[14] Under headmaster William Coe Collar (1867–1907), the school quadrupled in size and became the now-familiar college-preparatory institution.

[18] When Collar retired in 1907, Harvard president Charles Eliot (no relation[19]) said that "[t]here is no better preparatory school in the country.

[21] Collar financed this expansion by imposing tuition fees for the first time in Roxbury Latin's history, starting in 1882.

In accordance with the country day school movement, which argued that students should be educated outside the distractions and pollution of the city, Roxbury Latin's affluent alumni had demanded that the school move from Roxbury (which was now a working-class neighborhood) to a more suburban location.

In the 1944–45 school year, Roxbury Latin educated a roughly equal number of Protestants and Catholics.

[36] However, a proposal to admit girls was rejected in the 1970s,[37] and Roxbury Latin remains a boys' school to this day.

[41] Roxbury Latin has been recognized in several lists of schools that send their students to selective universities.

In the five-year period from 2019 to 2023, Roxbury Latin placed 84 students at Ivy League schools, nearly half of whom (38) attended Harvard College.

"[41] Previously, the 54 students in the Class of 2022 took 137 AP examinations by the end of their junior year, and 74% of the papers received a 4 or a 5.

"[51] However, after financial aid is taken into consideration, other day schools may still offer competitive tuition packages once a student is admitted.

Roxbury Latin and athletic rivals Belmont Hill and Nobles all claim to meet 100% of admitted students' demonstrated financial need.

[50][52][53] However, since Roxbury Latin is the only need-blind school out of these three, a prospective student seeking financial aid may have a better chance of obtaining admission to RL.

[57] The school offers varsity, junior varsity and lower-level teams in football, cross country, soccer (fall), basketball, ice hockey, wrestling (winter), baseball, tennis, lacrosse, and track and field (spring).

[58] Teams of note include: Roxbury Latin offers a school newspaper, a yearbook, an art magazine called Forum, several language clubs, a debate team, a Model United Nations group, and various community service clubs.

The theater program offers RL students the opportunity to meet girls from neighboring schools.