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 that 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.

Douglas County is located in the U.S. state of Kansas. Its county seat and most populous city is Lawrence. As of the 2020 census, the county population was 118,785, making it the fifth-most populous county in Kansas. The county was named after Stephen Douglas, a U.S. Senator from Illinois and advocate for the popular sovereignty choice in the Kansas slavery debate.