American Anti-Slavery Society

US association for the promotion of the abolition of slavery, active 1833–70. It was established by the brothers Arthur Tappan and Lewis Tappan, and William Lloyd Garrison, an uncompromising immediatist (campaigner for the immediate emancipation of all slaves), who became the Society's main leader. Other notable members included Wendell Phillips and Theodore Dwight Weld.

The activities of the American Anti-Slavery Society included organizing meetings and lectures, circulating antislavery petitions and sending them to US Congress, and publishing journals and pamphlets. Garrison's uncompromising approach alienated many members, who disagreed with his rejection of political means and his insistence on the inclusion of women in the organization. In 1839 less radical members, including the Tappan brothers, left the society to form the American and Foreign Anti-Slavery Society, which led to the creation of the Liberty Party in 1840. The American Anti-Slavery Society formally disbanded in 1870, after slavery was abolished and African Americans were granted basic constitutional rights.