Fugitive Slave Laws, or The 1850 Law, in United States history, legislation to assure slave-holders that runaway slaves would be returned. Fugitive slave laws denied to slaves any rights in proceedings for restoring them to bondage. The laws also forbade anyone to assist slaves to freedom.

Federal laws for the return of fugitive slaves were in accord with a precedent set in North American colonies before the United States was established. Northern as well as Southern colonies had laws requiring officials and private persons to aid in the recovery of fugitive slaves. The colonial laws also applied to Indians and white persons who were bound, or indentured.

The first federal law relating to fugitive slaves was enacted in 1793. It required state governments to return runaway slaves.

The Fugitive Slave Law of 1850 was enacted as part of the Compromise of 1850, a series of bills dealing with the slavery question that were sponsored in Congress by Henry Clay. Under this law, all citizens were subject to fines and imprisonment for harboring, concealing, or otherwise aiding runaway slaves. The law provoked much indignation among Northerners and led Harriet Beecher Stowe to write the antislavery novel Uncle Tom's Cabin (1852). Opponents of slavery increased the activity of the Underground Railroad, a secret system for helping blacks escape to freedom, and at least 10 Northern states passed “personal liberty” laws that sought to nullify the law. Southerners, pointing out that the law was backed by the U.S. Constitution (Article IV, Section 2), bitterly resented the Northern attitude.

The law was repealed in 1864, during the Civil War.