Hancock Lee Jackson (May 12, 1796 – March 19, 1876) was an American lawyer and politician who served as the 13th Governor of Missouri in 1857.

In 1829 he entered politics as a Democrat when he became sheriff of Randolph County, a position he held for two terms.

He also served as a delegate to the 1845 Missouri Constitutional Convention, During the Mexican–American War, he raised a company of volunteers and was elected commander with the rank of captain.

Robert Marcellus Stewart won the October contest to complete Polk's term, and Jackson resumed his duties as Lieutenant Governor.

The two share a great-grandfather, Joseph Jackson Sr. Jackson was then appointed United States Marshal for the Western District of Missouri, a post he held until Republican nominee Abraham Lincoln won the presidency in 1860 and replaced federal appointees with members of his own party after being inaugurated in 1861.