Big Brothers Big Sisters of Eastern Massachusetts is the heavyweight of the network in New England. With about 4,000 active matches, it is the second-largest Big Brothers Big Sisters affiliate in the country, behind only the Texas Lone Star agency. It covers a wide stretch of the state, from Boston and Cambridge out to Cape Cod and the Islands, and Mark O'Donnell leads it as President and CEO. The agency runs three flavors of mentoring, including an unusual college-based program that brings kids onto university campuses to meet their Bigs.
The work is the same one-to-one mentoring that Big Brothers Big Sisters has done for more than a century, run here at unusual scale. Children, called Littles, are matched with screened adult volunteers, called Bigs, and professional staff support each match so it holds together over time. Most of the kids come from families who sought out the match, and many face the kind of stacked challenges that one steady, caring adult can help carry. Running 4,000 matches at once takes a large staff and a deep volunteer pipeline, and the agency's standing as the second-largest affiliate nationally reflects how much of both it has built across Eastern Massachusetts.
Mark O'Donnell serves as President and CEO. He works with a senior team that includes Chief Program Officer Terrence McCarron, Vice President of Program Services Caitlin McNee, and Chief Development Officer Sara Conahan, with Rosemary Sheehan chairing the board. At this size, leadership is mostly about keeping match quality high while the numbers stay large, which is harder than it sounds: it is easy to grow a mentoring agency on paper and much harder to keep thousands of individual relationships genuinely supported. The agency marks its standout matches and volunteers each year at a spring awards event that has drawn coverage from the Boston Globe.
The service area is broad and uneven. Boston and Cambridge supply a dense pool of professional volunteers and corporate partners, which is why the site-based program does so well there. Out on Cape Cod, Martha's Vineyard, and Nantucket the picture flips: the year-round population is smaller and more spread out, the seasonal economy stretches family budgets, and reaching kids takes more effort per match. Covering both the urban core and the harder-to-serve coastal and island communities under one agency is part of what makes this affiliate as large as it is.
Matches meet for about an hour at a school or after-school site. The fixed time and place suit busy professionals, and it is the most popular entry point in Boston and Cambridge.
The traditional model. A Big and Little meet out in their community on their own schedule, doing activities they choose together.
An approach the agency leans on heavily: partner colleges and universities host children from harder-to-reach areas on campus to meet their mentors, opening a window onto higher education at the same time.
Applications go through emassbigs.org, followed by an interview and a background check before you are matched. The agency's range of programs is useful here, because it lets volunteers pick the level of commitment that fits their life. A young professional in Boston who cannot give up weekends might start with a weekly hour in the site-based program, while someone with more flexibility might take on a full community-based match. The standard expectation is to stay committed for at least a year so the relationship has room to grow.
Donations go through emassbigs.org, and the agency is a 501(c)(3), so gifts are tax-deductible. At this scale, money mostly pays for people: the staff who recruit and screen volunteers, run background checks, make the matches, and check in on thousands of pairs month after month. That match-support layer is what separates a well-run mentoring agency from a list of names, and it is the part that donations protect.
Massachusetts has no shortage of youth nonprofits, from the Boys & Girls Clubs of Boston to City Year and a long list of tutoring and after-school groups. Most of those work in group settings. Big Brothers Big Sisters of Eastern Massachusetts is the largest provider in the state of the supported one-to-one match, and its size gives it reach that smaller mentoring programs cannot match, including the college-based model that puts kids on university campuses. For a volunteer who wants a single, lasting relationship with one child, or a donor who wants scale and a long track record, it is the obvious starting point in the region.
Sources: Big Brothers Big Sisters of Eastern Massachusetts website, leadership page, and program pages (emassbigs.org), the agency's GuideStar profile (EIN 04-2074462), and April 2026 Boston Globe coverage of its annual awards event. Match count and national ranking per the agency's published figures. We are not affiliated with Big Brothers Big Sisters of Eastern Massachusetts and receive no compensation for this listing. Spotted an error? [email protected]
More Massachusetts and mentoring resources