The Lecompton Constitution (1858) was the second of four proposed constitutions for the state of Kansas. Named for the city of Lecompton where it was drafted, it was strongly pro-slavery. It never went into effect.

Lecompton is a city in Douglas County, Kansas, United States. As of the 2020 census, the population of the city was 588. Lecompton was the de jure territorial capital of Kansas from 1855 to 1861, and the Douglas County seat from 1855 to 1858. Anti-slavery Lawrence became the de facto capital during the latter part of this period, when the county seat was moved there. This time period was known as Bleeding Kansas, due to the violence perpetrated by the pro-slavery, and to a lesser extent the anti-slavery, factions in the eastern part of the state. Lecompton was a hotbed of pro-slavery sentiment during the mid-1800s.