Clemens is a Late Latin masculine name meaning "merciful". Clemens (or sometimes 'Klemens') may refer to:
People - family name
- Andrew Clemens (b.1852 or 1857–1894), American folk artist
- Barry Clemens (born 1943), American basketball player
- Brian Clemens (born 1931), British screenwriter and television producer
- Clayton Clemens, American Professor of Government
- Dan Clemens (born 1945), American politician
- George T. Clemens (1902–1992), American cinematographer
- Harold W. Clemens (1918–1998), American politician
- Isaac Clemens (1815–1880), Canadian farmer and politician
- Jacob Clemens non Papa (c. 1510 to 1515–1555 or 1556), Franco-Flemish composer of the Renaissance
- James Clemens, pen name of author Jim Czajkowski
- James Clemens, Jr. (1791–1878), a US Senator
- Jean Clemens (1880–1909), youngest daughter of Samuel Langhorne Clemens (Mark Twain)
- Jeremiah Clemens (1814–1865), U.S. senator and novelist
- Josef Clemens (born 1947), German bishop
- Joseph Clemens (1862–1936), American missionary and plant collector
- Joseph Clemens of Bavaria (1671–1723), German archbishop
- Kellen Clemens (born 1983), American football player
- Koby Clemens (born 1986), American baseball player
- Marcus Arrecinus Clemens (disambiguation), multiple people
- Martin Clemens, British World War II soldier and Solomon Islands coastwatcher
- Mary Strong Clemens (1873–1968), American botanist and plant collector
- Olivia Langdon Clemens (1845–1904), wife of Samuel Langhorne Clemens (Mark Twain)
- Orion Clemens (1825–1987), brother of Samuel Langhorne Clemens (Mark Twain)
- Roger Clemens (born 1962), American baseball player
- Samuel Langhorne Clemens, better known as Mark Twain (1835–1910), author
- Sherrard Clemens (1820–1881), American politician and lawyer
- Titus Flavius Clemens (consul), great-nephew of the Roman Emperor Vespasian and (as Flavius Clemens) a saint in the Greek Orthodox Church (Clement of Alexandria)
- William Clemens (film director) (1905–1980), American film director
People - given name
- Clemens (entertainer), (born 1979), real name Clemens Legolas Telling, Danish rapper, singer, music writer, actor
- Clemens (impostor) (d. c. 15 AD), ancient Roman
- Clemens Arnold (born 1978), German field hockey player
- Clemens Baeumker (1853–1924), German historian of philosophy
- Clemens Bollen (born 1948), German politician
- Clemens Brentano (1778–1842), German poet and novelist
- Clemens Denhardt (1852–1929), German explorer of Africa
- Clemens Fritz (born 1980), German footballer
- Arno Clemens Gaebelein (1861–1945), Methodist minister
- Clemens Maria Hofbauer (1751–1820), patron saint of Vienna
- Clemens Holzmeister (1886–1983), Austrian architect
- Clemens Kalischer (born 1921), German-American photographer
- Clemens Klotz (1886–1969), German architect
- Clemens Krauss (1893–1954), Austrian conductor
- Clemens August Graf von Galen (1878–1946), German count, Bishop of Münster, and Cardinal of the Roman Catholic Church
- Clemens von Pirquet (1874–1929), Austrian scientist and pediatrician
- Prince Clemens Wenceslaus of Saxony (1739–1812), German Archbishop
- Clemens Westerhof (born 1940), Dutch football manager
- Clemens Wilmenrod (1906–1967), German television cook
- Clemens Winkler (1838–1904), German chemist
Places
- Mount Clemens, Michigan, American city
- Mount Clemens High School
- Munsinger Gardens and Clemens Gardens, gardens in St Cloud, Minnesota, USA
Other
- Clemens Automobile Company Building, listed on the National Register of Historic Places in Polk County, Iowa
- See Cambridge Latin Course for Clemens, a fictional slave
- Clemens church, Swedish church building
- Clemens Family Corporation, American holding company
- Dr. Jonathon Clemens, a character in the 1992 film Alien 3 played by the British Actor Charles Dance