John Caldwell Calhoun (/kælˈhuːn/; March 18, 1782 – March 31, 1850) was an American statesman from the Democratic party and political theorist from South Carolina who served as the seventh vice president of the United States from 1825 to 1832. He is remembered for strongly defending slavery and for advancing the concept of minority rights in politics, which he did in the context of protecting the interests of the white South when it was outnumbered by Northerners. He began his political career as a nationalist, modernizer, and proponent of a strong national government and protective tariffs. In the late 1820s, his views changed radically, and he became a leading proponent of states' rights, limited government, nullification, and opposition to high tariffs —he saw Northern acceptance of these policies as a condition of the South remaining in the Union. His beliefs and warnings heavily influenced the South's secession from the Union in 1860–1861.

John C. Calhoun, a James Madison-class fleet ballistic missile submarine, was the only ship of the United States Navy to be named for John C. Calhoun (1782–1850), the Democratic legislator and statesman.

John C. Calhoun is a marble sculpture depicting the American statesman of the same name by Frederick Ruckstull, installed in the United States Capitol 's crypt, in Washington, D.C., as part of the National Statuary Hall Collection. The statue was gifted by the U.S. state of South Carolina in 1910.

John C. Calhoun was a longtime Pittsburgh Police leader, who served as Pittsburgh Police Chief from 1921 until 1923.