The Barbary Wars were a series of two wars fought by the United States, Sweden, and the Kingdom of Sicily against the Barbary states (including Tunis, Algiers, and Tripoli) and Morocco of North Africa in the early 19th century. Sweden had been at war with the Tripolitans since 1800 and was joined by the newly independent U.S.^{[unreliable source?]} The First Barbary War extended from 10 May 1801 to 10 June 1805, with the Second Barbary War lasting only three days, ending on 19 June 1815. The Barbary Wars were the first major American wars fought entirely outside the New World, and in the Arab World.

The wars were largely a reaction to piracy by the Barbary states. Since the 16th century, North African pirates had captured ships and even raided European coastal areas across the Mediterranean Sea. Originally starting out with the goal of capturing individuals for the domestic North African slave trade, the focus later shifted to kidnapping for ransom. By the 19th century, pirate activity had declined, but Barbary pirates continued to demand tribute from American merchant vessels in the Mediterranean. Refusal to pay would result in the capture of American ships and goods, and often the enslavement or ransoming of crew members.

After Thomas Jefferson became president of the U.S. in March 1801, he sent a U.S. Navy fleet to the Mediterranean to combat the Barbary pirates. The fleet bombarded numerous fortified cities in present-day Libya, Tunisia, and Algeria, ultimately extracting concessions of safe conduct from the Barbary states and ending the first war.

During the War of 1812, with the encouragement of the United Kingdom, the Barbary corsairs resumed their attacks on American vessels. Following the conclusion of the War of 1812 and America's peace with Britain, James Madison, Jefferson's successor, directed military forces against the Barbary states in the Second Barbary War. Lasting only three days, the second conflict ended the need for further tribute from the United States, granted the U.S. full shipping rights in the Mediterranean Sea, and significantly reduced incidents of piracy in the region.

The Barbary corsairs were pirates and privateers who operated out of North Africa, based primarily in the ports of Tunis, Tripoli, and Algiers. This area was known in Europe as the Barbary Coast, in reference to the Berbers. The corsairs predation covered the Mediterranean, and extended south along West Africa's Atlantic, even to the eastern coast of Brazil, into the North Atlantic Ocean raiding the coasts of Ireland and western Britain, and going as far north as Iceland, but they primarily operated in the western Mediterranean. In addition to seizing ships, they engaged in razzias, raids on European coastal towns and villages, mainly in Italy, France, Spain, and Portugal, but also in England, Scotland, the Netherlands, Ireland, and as far away as Iceland. The main purpose of their attacks was to capture Europeans for the slave market in North Africa.

The Barbary states were nominally part of the Ottoman Empire, but in practice they were operating independently and the Ottoman government in Constantinople was not involved.

Since the 1600s, the Barbary pirates had attacked British shipping along the northern coast of Africa, holding captives for ransom or enslaving them. Ransoms were generally raised by families and local church groups, including the Roman Catholic Church. The British became familiar with captivity narratives written by Barbary pirates' prisoners and slaves.

During the American Revolutionary War, the pirates attacked American ships. On December 20, 1777, Morocco's sultan Mohammed III declared that merchant ships of the new American nation would be under the protection of the sultanate and could thus enjoy safe passage into the Mediterranean and along the coast. The Moroccan-American Treaty of Friendship stands as America's oldest unbroken friendship treaty with a foreign power. In 1787, Morocco became one of the first nations to recognize the United States.