Jacksonian democracy was a 19th century political philosophy in the United States that expanded suffrage to most white men over the age of 21, and restructured a number of federal institutions. Originating with the seventh U.S. president, Andrew Jackson and his supporters, it became the nation's dominant political worldview for a generation. The term itself was in active use by the 1830s.

This era, called the Jacksonian Era or Second Party System by historians and political scientists, lasted roughly from Jackson's 1828 election as president until slavery became the dominant issue with the passage of the Kansas–Nebraska Act in 1854 and the political repercussions of the American Civil War dramatically reshaped American politics. It emerged when the long-dominant Democratic-Republican Party became factionalized around the 1824 United States presidential election. Jackson's supporters began to form the modern Democratic Party. His political rivals John Quincy Adams and Henry Clay created the National Republican Party, which would afterward combine with other anti-Jackson political groups to form the Whig Party.

Broadly speaking, the era was characterized by a democratic spirit. It built upon Jackson's equal political policy, subsequent to ending what he termed a monopoly of government by elites. Even before the Jacksonian era began, suffrage had been extended to a majority of white male adult citizens, a result which the Jacksonians celebrated. Jacksonian democracy also promoted the strength of the presidency and the executive branch at the expense of the United States Congress, while also seeking to broaden the public's participation in government. The Jacksonians demanded elected, not appointed, judges and rewrote many state constitutions to reflect the new values. In national terms, they favored geographical expansionism, justifying it in terms of manifest destiny. There was usually a consensus among both Jacksonians and Whigs that battles over slavery should be avoided.

Jackson's expansion of democracy was largely limited to European Americans, and voting rights were extended to adult white males only. There was little or no change, and in many cases a reduction of the rights of African Americans and Native Americans during the extensive period of Jacksonian democracy, spanning from 1829 to 1860.