Free-Staters was the name given to settlers in Kansas Territory during the "Bleeding Kansas" period in the 1850s who opposed the expansion of slavery. The name derives from the term "free state", that is, a U.S. state without slavery. Many of the "free-staters" joined the Jayhawkers in their fight against slavery and to make Kansas a free state.

The Territory of Kansas was an organized incorporated territory of the United States that existed from May 30, 1854, until January 29, 1861, when the eastern portion of the territory was admitted to the Union as the free state of Kansas.