The Democratic-Republican Party, also referred to as the Jeffersonian Republican Party and known at the time as the Republican Party and occasional other names, was an American political party founded by Thomas Jefferson and James Madison in the early 1790s that championed republicanism, agrarianism, political equality, and expansionism. The party became increasingly dominant after the 1800 elections as the opposing Federalist Party collapsed. The Democratic-Republicans later splintered during the 1824 presidential election. The majority faction of the Democratic-Republicans eventually coalesced into the modern Democratic Party, while the minority faction ultimately formed the core of what became the Whig Party.The Democratic-Republican Party originated as a faction in Congress that opposed the centralizing policies of Alexander Hamilton, who served as Secretary of the Treasury under President George Washington. The Democratic-Republicans and the opposing Federalist Party each became more cohesive during Washington's second term, partly as a result of the debate over the Jay Treaty. Though he was defeated by Federalist John Adams in the 1796 presidential election, Jefferson and his Democratic-Republican allies came into power following the 1800 elections. As president, Jefferson presided over a reduction in the national debt and government spending, and completed the Louisiana Purchase with France.

Madison succeeded Jefferson as president in 1809 and led the country during the largely inconclusive War of 1812 with Britain. After the war, Madison and his congressional allies established the Second Bank of the United States and implemented protective tariffs, marking a move away from the party's earlier emphasis on states' rights and a strict construction of the United States Constitution. The Federalists collapsed after 1815, beginning a period known as the Era of Good Feelings. Lacking an effective opposition, the Democratic-Republicans split into groups after the 1824 presidential election; one faction supported President John Quincy Adams, while the other faction backed General Andrew Jackson. Jackson's faction eventually coalesced into the Democratic Party, while supporters of Adams became known as the National Republican Party, which itself later merged into the Whig Party.

Democratic-Republicans were deeply committed to the principles of republicanism, which they feared were threatened by the supposed aristocratic tendencies of the Federalists. During the 1790s, the party strongly opposed Federalist programs, including the national bank. After the War of 1812, Madison and many other party leaders came to accept the need for a national bank and federally funded infrastructure projects. In foreign affairs, the party advocated western expansion and tended to favor France over Britain, though the party's pro-French stance faded after Napoleon took power. The Democratic-Republicans were strongest in the South and the western frontier, and weakest in New England.