Residents of Brookline tend toward liberal values, economic and cultural factors keep this section of the Boston metropolitan area less diverse than its neighbor across the Charles River, Cambridge. Brookline's liberalism and diversity are relatively new developments in the town's history. In the 19th century, Brookline, which had been called "the richest town in America", was a sanctuary for the wealthy, where Boston's elites built their summer homes. Brookline is still typically regarded by locals as a wealthier suburb of Boston (along with Newton), given the number of wealthy individuals (CEOs, high-profile executives, famous musicians and actors) who reside there.
Brookline is known in the Boston area for its large population of Russian and Israeli immigrants and numerous synagogues. Jewish culture is very strong in Brookline; the Jewish population was estimated in 2002 at 20,300 - over 35% of the town's population.