Kelsey is an English surname. In modern times Kelsey has also become a given name for boys and girls in English-speaking countries. It may come from an Old English place name in Lincolnshire, from a word meaning "island of the ships" in Irish and Scots, or even a Norwegian one meaning "a dweller on the island, by the water".

Kelsey may refer to:

• Edward Kelsey (1930–2019), English actor
• Greg Kelsey (1893–1967), stage name of British-born actor William Gregory Kelsall
• Ian Kelsey (born 1966), British television actor
• Linda Kelsey (born 1946), American television actress

• Arthur Kelsey (1871–1955), English footballer
• Jack Kelsey (1929–1992), Welsh football goalkeeper
• Lloyd Kelsey (1897–1948), American tug-of-war competitor

• Charles Kelsey (New York politician) (1821–1866), American politician
• Edwin B. Kelsey, American politician, lawyer, and businessman
• Thomas Kelsey (died c. 1680), important figure in the government of Oliver Cromwell
• Tim Kelsey director for patients and information in the National Health Service
• William H. Kelsey (1812–1879), U.S. Congressman (1855–1859)

• Benjamin Kelsey (1813–1889), California pioneer, husband of Nancy Kelsey.
• Benjamin S. Kelsey (1906–1981), American Air Force test pilot and aeronautical engineer
• Carl Kelsey (1870–1953), American sociologist
• Frances Oldham Kelsey (1914–2015), naturalized American pharmacologist
• Henry Kelsey (c. 1667–1724), English fur trader, explorer, helped found Hudson's Bay Company
• Hugh Kelsey (1926–1995), Scottish bridge player and writer
• John Kelsey (cryptanalyst), cryptographer currently working at NIST
• Nancy Kelsey, California pioneer, "the Betsy Ross of California" for sewing the Bear Flag

• Kelsay, Indian scout
• Kelsey (given name)