Although China’s Taiping Rebellion (1851-64) is perhaps history’s bloodiest civil war it has remained largely beyond the purview of genocide scholars, and its historiography has generally portrayed it as a “progressive” or “revolutionary” movement. This essay argues, however, that in its alien ideology derived from Protestantism and pre-Confucian millenarianism guided by the visions of Hong Xiuquan (1813-1864); radical attempts at social leveling; dismantling of Confucian culture and society; and elimination of select ethnic and religious groups, this attempt to create a theocratic “heavenly kingdom of great peace” (taiping tianguo) bears the hallmarks of current definitions of genocide and departs in crucial ways from even the most massive and sanguinary conflicts marking the Chinese past.