The Liberator (1831–1865) was a weekly abolitionist newspaper, printed and published in Boston by William Lloyd Garrison and, through 1839, by Isaac Knapp.

Religious rather than political, it appealed to the moral conscience of its readers, urging them to demand immediate freeing of the slaves ("immediatism").

Despite its modest circulation of 3,000, it had prominent and influential readers, including all the abolitionist leaders, among them Frederick Douglass, Beriah Green, Arthur and Lewis Tappan, and Alfred Niger.

It frequently printed or reprinted letters, reports, sermons, and news stories relating to American slavery, becoming a sort of community bulletin board for the new abolitionist movement that Garrison helped foster.

[1] Although its circulation was only about 3,000, and three-quarters of subscribers (in 1834) were African Americans,[2] the newspaper earned nationwide notoriety for its uncompromising advocacy of "immediate and complete emancipation of all slaves" in the United States.

Garrison set the tone for the paper in his famous open letter "To the Public" in the first issue: ... Assenting to the "self-evident truth" maintained in the American Declaration of Independence, "that all men are created equal, and endowed by their Creator with certain inalienable rights—among which are life, liberty and the pursuit of happiness," I shall strenuously contend for the immediate enfranchisement of our slave population.

In Park-street Church, on the Fourth of July, 1829, in an address on slavery, I unreflectingly assented to the popular but pernicious doctrine of gradual abolition.

[7] Between January 7, 1832 and May 4, 1833, the Liberator published six articles by Maria W. Stewart, an abolitionist and one of the first American women to lecture before mixed-race and mixed-gender audiences.

She sent a letter to William Lloyd Garrison recalling her experiences as a member of an upper class, white, slaveholding family.

Eventually escalation of the situation led to destruction of the society's antislavery sign, and even calls to lynch Garrison, around whose neck a piece of rope made into a noose was put.