The Democratic-Republican Party, is the political party organized by Thomas Jefferson and James Madison in 1791. It stood in oposition to the Federalist Party and dominated American politics from 1800 to the 1820s, during the First Party System.

Contemporary and historical sources call it the Republican Party, while political scientists use the hyphenated version. Historians also refer to the party as the Jeffersonian republicans, to distinguish it from the modern Republican Party, which was founded in 1854.

The organization formed first as an "Anti-Administration" secret meeting in the national capital (Philadelphia) to oppose the programs of Secretary for the Treasury Alexander Hamilton. Jefferson needed to have a nationwide party to counteract the Federalists, a nationwide party organized by Hamilton. Foreign affairs took a leading role in 1794-95 as the Republicans vigorously opposed the Jay Treaty with Britain, which was then at war with France. Republicans saw France as more democratic after its revolution, while Britain represented the hated monarchy. The party denounced many of Hamilton's measures (especially the national bank) as unconstitutional.

The party was strongest in the South and weakest in the Northeast; it favored states' rights and the primacy of the yeoman farmers. Republicans were deeply committed to the principles of republicanism, which they feared were threatened by the supposed monarchical tendencies of the Hamiltonians/Federalists. The party came to power with the election of Jefferson in 1801. The Federalists—too elitist to appeal to most people—faded away, and totally collapsed after 1815. The Republicans, despite internal divisions, dominated the First Party System until partisanship itself withered away during the Era of Good Feelings after 1816.

The party selected its presidential candidates in a caucus of members of Congress. They included Thomas Jefferson (nominated 1796; elected 1800-1, 1804), James Madison (1808, 1812), James Monroe (1816, 1820). By 1824 the caucus system practically collapsed. After 1800, the party dominated Congress and most state governments outside New England. By 1824 the party was split 4 ways and lacked a center. One remnant followed Andrew Jackson and Martin Van Buren into the new Democratic Party by 1828. That party still exists. Another remnant led by John Quincy Adams and Henry Clay formed the National Republicans in 1828; It held its first convention in late 1831 in Baltimore. It morphed into the Whig Party by 1835. The Whig Party fell apart in the mid-1850s because it could not bridge North-South differences on slavery, while the Democrats held together by taking positions favored by the South.