Abolitionism, or the abolitionist movement, is the movement to end slavery and liberate slaves around the world.

The first country to fully outlaw slavery was France in 1315, but it was later used in its colonies. Under the actions of Toyotomi Hideyoshi, chattel slavery has been abolished across Japan since 1590, though other forms of forced labour were used during World War II. The first and only country to self-liberate from slavery was actually a former French colony, Haiti, as a result of the Revolution of 1791–1804. The British abolitionist movement began in the late 18th century, and the 1772 Somersett case established that slavery did not exist in English law. In 1807, the slave trade was made illegal throughout the British Empire, though existing slaves in British colonies were not liberated until the Slavery Abolition Act in 1833. Vermont was the first state in America to abolish slavery in 1777. By 1804, the rest of the northern states had abolished slavery but it remained legal in southern states. By 1808, the United States outlawed the importation of slaves but did not ban slavery outright until 1865.

In Eastern Europe, groups organized to abolish the enslavement of the Roma in Wallachia and Moldavia between 1843 and 1855, and to emancipate the serfs in Russia in 1861. The United States would pass the 13th Amendment in December 1865 after having just fought a bloody Civil War, ending slavery "except as a punishment for crime".