The Nullifier Party was an American political party based in South Carolina in the 1830s. Considered an early American third party, it was started by John C. Calhoun in 1828.

The Nullifier Party was a states' rights, pro-slavery party that supported strict constructionism with regards to the U.S. government's enumerated powers, holding that states could nullify federal laws within their borders. It narrowly missed claiming the unofficial title of being the first ever third party to be created within the United States—that title belongs to the Anti-Masonic Party, which was created in New York in February 1828. The Nullifier Party had several members in both houses of the Congress between 1831 and 1839. Calhoun outlined the principles of the party in his South Carolina Exposition and Protest (1828), a reaction to the "Tariff of Abominations" passed by Congress and signed into law by President John Quincy Adams. (A similar position had been staked out by the Kentucky and Virginia Resolutions thirty years prior, though those Resolutions had stopped short of actually advocating nullification.)

The Nullifier Party operated almost exclusively in South Carolina. It stood in strong opposition to President Andrew Jackson. John Floyd was supported by the Nullifier Party in the 1832 presidential election, and he received South Carolina's 11 votes in the electoral college. Floyd was not a candidate and had himself unsuccessfully tried to convince Calhoun to run for President. The party's candidate for Vice President was the Massachusetts-based political economist Henry Lee. Some Nullifiers joined the newly formed Whig Party after the 1832 election, attracted by its opposition to Jackson and its depiction of Jackson as a monarch. After President Andrew Jackson left office, Calhoun and most of his followers rejoined the Democratic Party.