Littleton Purnell Dennis (July 21, 1786 – April 14, 1834) was an American politician who served in the United States House of Representatives, Maryland House of Delegates, Maryland State Senate, and in the Maryland Executive Council.

Dennis was born July 21, 1786, at "Beverly" in Pocomoke City, Worcester County, Maryland,^[1] the son of Henry Dennis and Anne Dennis (née Purnell).^[2] Dennis was tutored at home.^[2] He thereafter attended Washington Academy of Somerset County, Maryland, and graduated from Yale College in 1803. He studied law, was admitted to the bar, and commenced practice.^[1][2] Dennis was a nephew of John Dennis (1771–1806) and cousin of Littleton Dennis Jr. and John Dennis (1807–1859).^[1]

In 1810; 1815 and 1816; and again from 1819 to 1821, Dennis served as a member of the Maryland House of Delegates.^[2] He was a member of the executive council of Maryland in 1829.^[1] From 1827 until resigning in 1833, he served in the Maryland Senate.^[2] Dennis was elected as an Anti-Jacksonian to the United States House of Representatives in 1832 and served from March 4, 1833, until his death in office in 1834.^[1] Dennis affiliated himself with the newly-founded Whig Party.^[2]

Dennis was a presidential elector in 1812, 1824, and 1828.^[2]

Dennis never was married and had no children.^[2] He died April 14, 1834, while in Washington, D.C. and was interred in the Congressional Cemetery there.^[1]

• List of United States Congress members who died in office (1790–1899)