Martyrologies or martyrdom narratives have been a crucial source of social criticism in abolitionist struggles for racial justice and equality: from Denmark Vesey and Francis MacIntosh to Elijiah Parish Lovejoy and John Brown in the antebellum era, and from Trayvon Martin, Michael Brown, and George Floyd to Breonna Taylor and Renee Good in our own time. This paper examines the significance of martyrdom discourse in the antebellum anti-slavery movement for immediate abolition as well as abolitionist martyrdom discourse in our own time. In 1824, a British Dissenting Quaker abolitionist, Elizabeth Heyrick, published "Immediate, not Gradual, Abolition" which both labeled and fueled radical movements for trans-Atlantic "immediate abolition" including the radical Garrisonian wing of the American anti-slavery movement. After meeting with Garrisonians (1834-1836), another British Unitarian, the proto-sociologist, Harriet Martineau, dubbed the 1830s the "Martyr Age of the United States of America" (1838). As if expanding the martyrological canon, in his bold "Address to the Slaves of the United States," (1843)—one of the most radical religious calls for insurrection in antebellum America—the abolitionist Presbyterian minister, Henry Highland Garnet, linked Black radicals to traditions of freedom fighters and martyrs or "martyr[s] to freedom." Transcendentalists, including Henry David Thoreau, Wendell Phillips, and Ralph Waldo Emerson, were among the first to hail John Brown as an abolitionist martyr under, as Thoreau put it, "a government that pretends to be Christian and crucifies a million Christs every day!" Having examined the significance of martyrdom discourse for antebellum abolitionism and the quest for racial equality, I argue that martyrdom discourse—from individual figures to "Say Their Names" campaigns--continues to be a powerful form of social criticism in abolitionist movements today.