In politics and government, a spoils system (also known as a patronage system) is a practice in which a political party, after winning an election, gives government jobs to its supporters, friends (cronyism), and relatives (nepotism) as a reward for working toward victory, and as an incentive to keep working for the party. It contrasts with a merit system, where offices are awarded or promoted based on a measure of merit, independent of political activity.

The term was used particularly in the politics of the United States, where the federal government operated on a spoils system until the Pendleton Act was passed in 1883, following a civil service reform movement. Thereafter, the spoils system was largely replaced by a nonpartisan merit-based system at the federal level of the United States.

The term was derived from the phrase "to the victor belong the spoils" by New York Senator William L. Marcy, referring to the victory of Andrew Jackson in the election of 1828, with the term "spoils" meaning goods or benefits taken from the loser in a competition, election or military victory.

Similar spoils systems are common in other nations that traditionally have been based on tribal organization or other kinship groups and localism in general.

Although it is commonly thought that the spoils system was introduced by President Andrew Jackson, historical evidence does not support this view. Patronage came to the United States during its Colonial history, whereas in its modern form, the spoils system got introduced into U.S. politics during the administration of George Washington, whose outlook generally favored members of the Federalist Party. Sometimes, Washington is accused of introducing the system himself. In addition, both John Adams and Thomas Jefferson have also been accused, to a degree, of introducing the spoils system to U.S. politics.

Even before he entered the White House, some opponents of Jackson suggested that he had a habit of exploiting the public treasury. Samuel Clement, who had piloted steamboat troop transports for Jackson at the time of the Battle of New Orleans, pamphleteered in 1827:

"Some of those who zealously strive to increase the popularity, and promote the cause of general Jackson, figuratively say he will cleanse the Augean stable at Washington, meaning that he will expel the retainers at Washington and reduce the number of clerks in the secretaries offices. We have hitherto had but very little earnest of this disposition in the General; at New Orleans, the number of aides-de-camp which he had about him, I strongly suspect equated the number which Napoleon had, at the battle of Austerlitz or any other of his great battles; and if the General for the purpose of curtailing the public expenditures, should be disposed to reorganize the public offices, will any one have the hardihood to say, that he knows enough of the labour, and of the proper manner of conducting business in those offices to know how many clerks they require, and consequently how many he might with propriety send adrift; beside there are some reasons to doubt, whether the General has so very great an interest in preventing expenditures of public money, or whether he holds public property so sacred as some would have it believed he does."

In 1828, moderation was expected to prevail in the transfer of political power from one U.S. president to another. This had less to do with the ethics of politicians than it did with the fact the presidency had not transferred from one party to another since the election of 1800—known historically for the extraordinary steps the outgoing Federalist Party took to try and maintain as much influence as possible by exploiting their control over federal appointments up until their final hours in office (see: Marbury v. Madison and Midnight Judges Act). By 1816, the Federalists were no longer nationally viable, and the U.S. became effectively a one-party polity under the Democratic-Republican Party. The Jacksonian split after the 1824 election restored the two-party system. Jackson's first inauguration, on March 4, 1829, marked the first time since 1801 when one party yielded the presidency to another. A group of office seekers attended the event, explaining it as democratic enthusiasm. Jackson supporters had been lavished with promises of positions in return for political support. These promises were honored by a large number of removals after Jackson assumed power. At the beginning of Jackson's administration, fully 919 officials were removed from government positions, amounting to nearly 10 percent of all government postings. In 1913, a history of Tennessee commented, "It is said that in early life Jackson had made it a principle never to stand between a friend and a benefit. The converse seemed also to have been a principle: never to benefit an enemy. And those who were excluded from his friendship were excluded from preferment."