Southern Democrats are members of the U.S. Democratic Party who reside in the Southern United States.

Before the American Civil War, Southern Democrats mostly believed in Jacksonian democracy. In the 19th century, they defended slavery in the United States and promoted its expansion into the Western United States against the Free Soil opposition in the Northern United States. The United States presidential election of 1860 formalized the split in the Democratic Party and brought about the American Civil War. After the Reconstruction Era ended in the late 1870s, so-called redeemers were Southern Democrats who controlled all the southern states and disenfranchised African-Americans.

The monopoly that the Democratic Party held over most of the South showed signs of breaking apart in 1948, when many white Southern Democrats—upset by the policies of desegregation enacted during the administration of Democratic president Harry Truman—created the States' Rights Democratic Party. This new party, commonly referred to as the "Dixiecrats", nominated South Carolina governor Strom Thurmond for president. The new party collapsed after Truman unexpectedly won the 1948 United States presidential election.

Despite being a Southern Democrat himself, President Lyndon B. Johnson signed the Civil Rights Act of 1964 and the Voting Rights Act of 1965. These actions led to heavy opposition from Southern Democrats. Many scholars have stated that southern whites shifted to the Republican Party after a civil rights culture change and due to social conservatism.

Republicans first dominated presidential elections in the South, then won a majority of Southern gubernatorial and congressional elections after the 1994 Republican Revolution. By the 21st century, and especially after the 2010 midterm elections, the Republican Party had gained a solid advantage over the Democratic Party in most southern states.

Southern Democrats of the 21st century, such as Jon Ossoff and Raphael Warnock, are considerably more progressive than their predecessors. No Democrat has been elected president without winning at least 2 of the 11 former Confederate states, including winning at least one of Georgia or Florida.

The title of "Democrat" has its beginnings in the South, going back to the founding of the Democratic-Republican Party in 1793 by Thomas Jefferson and James Madison. It held to small government principles and distrusted the national government. Foreign policy was a major issue. After being the dominant party in U.S. politics from 1801 to 1829, the Democratic-Republicans split into two factions by 1828: the federalist National Republicans (who became the Whigs), and the Democrats. The Democrats and Whigs were evenly balanced in the 1830s and 1840s. However, by the 1850s, the Whigs disintegrated. Other opposition parties emerged but the Democrats were dominant. Northern Democrats were in serious opposition to Southern Democrats on the issue of slavery; Northern Democrats, led by Stephen Douglas, believed in Popular Sovereignty—letting the people of the territories vote on slavery. The Southern Democrats, reflecting the views of the late John C. Calhoun, insisted slavery was national.

The Democrats controlled the national government from 1853 until 1861, and presidents Pierce and Buchanan were friendly to Southern interests. In the North, the newly formed anti-slavery Republican Party came to power and dominated the electoral college. In the 1860 presidential election, the Republicans nominated Abraham Lincoln, but the divide among Democrats led to the nomination of two candidates: John C. Breckinridge of Kentucky represented Southern Democrats, and Stephen A. Douglas of Illinois represented Northern Democrats. Nevertheless, the Republicans had a majority of the electoral vote regardless of how the opposition split or joined and Abraham Lincoln was elected.