Slavery can only be abolished by raising the character of the people who compose the nation; and that can be done only by showing them a higher one.

Over the course of their twelve-year marriage which ended in Henry’s death from tuberculosis in 1842 Chapman had four children one of whom died in early childhood. Henry's parents were also enthusiastic abolitionists. In 1835 Chapman assumed the leadership of the Boston Anti-Slavery Bazaar which had been founded the previous year by Lydia Maria Child and Louisa Loring and remained in charge of the fair until 1858 when Maria Weston Chapman unilaterally made the decision to replace the bazaar with the Anti-Slavery Subscription Anniversary.

She was elected to the executive committee of the American Anti-Slavery Society in 1839 and from 1839 until 1842 Maria Weston Chapman served as editor of the anti-slavery journal Non-Resistant.