The Slave Power (often called the "Slaveocracy") was a term used in the United States ca. 1840-1865 to denounce the political power of the slaveholding class in the South. The argument was that this small group of rich men had seized political control of their own states and was trying to take over the national government in illegitimate fashion to use it to expand and protect slavery.

The main issue expressed by the phrase was distrust of the power of slave-owning oligarchs. Such distrust was shared by many who were not abolitionists, and who were motivated more by a perceived threat to whites than by concern over the treatment of slaves. Those who differed on many other issues (such as hating blacks or liking them, denouncing slavery as a sin or promising to guarantee its protection in the Deep South) could unite to attack the "slaveocracy." The "Free Soil" element emphasized that rich slave owners would move into new territory, use their cash to buy up all the good lands, then use their slaves to work the lands, leaving little opportunity room for free farmers. By 1854 the Free Soil Party had largely merged into the new Republican party