The sacking of Lawrence occurred on May 21, 1856, when pro-slavery settlers, led by Douglas County Sheriff Samuel J. Jones, attacked and ransacked Lawrence, Kansas, a town which had been founded by anti-slavery settlers from Massachusetts who were hoping to make Kansas a free state. The incident fueled the irregular conflict in Kansas Territory that later became known as Bleeding Kansas.

The human cost of the attack was low: only one persona member of the pro-slavery gangwas killed, and his death was accidental. However, Jones and his men halted production of the Free-State newspapers the Kansas Free State and the Herald of Freedom (with the former ceasing publication altogether and the latter taking months to once again start up). The pro-slavery men also destroyed the Free State Hotel and Charles L. Robinson's house.

Lawrence is the county seat of Douglas County, United States, and sixth-largest city in Kansas. It is in the northeastern sector of the state, astride Interstate 70, between the Kansas and Wakarusa Rivers. As of the 2020 census, the population of the city was 94,934. Lawrence is a college town and the home to both the University of Kansas and Haskell Indian Nations University.

Lawrence was founded by the New England Emigrant Aid Company (NEEAC), and was named for Amos A. Lawrence, a Republican abolitionist originally from Massachusetts, who offered financial aid and support for the settlement. Lawrence was central to the "Bleeding Kansas" period (1854–1861), and the site of the Wakarusa War (1855) and the Sacking of Lawrence (1856). During the American Civil War it was also the site of the Lawrence massacre (1863).

Lawrence began as a center of free-state politics. Its economy diversified into many industries, including agriculture, manufacturing, and education, beginning with the founding of the University of Kansas in 1865 and Haskell Indian Nations University in 1884.