Clemens is a Late Latin, German, and Dutch masculine given name and a surname, meaning "merciful".

Notable people with the name include:

Surname

• Adelaide Clemens (born 1989), Australian actress.
• Andrew Clemens (b. 1852 or 1857–1894), American folk artist
• Aurelius Prudentius Clemens, 4th century Roman poet
• Avery Jae Clemens, Australian model and social media influencer
• Barry Clemens (born 1943), American basketball player
• Bert A. Clemens (1874–1935), American politician
• Brian Clemens (1931–2015), British screenwriter and television producer
• Clayton Clemens, American Professor of Government
• Dan Clemens (1945–2019), American politician
• Gabriel Clemens (born 1983), German darts player
• George T. Clemens (1902–1992), American cinematographer
• Harold W. Clemens (1918–1998), American politician
• C. Herbert Clemens (born 1939), American mathematician
• 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 (disambiguation), multiple people
• 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
• Kody Clemens (born 1996), 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
• Mazie E. Clemens (1890s–1952), American journalist and WWI war correspondent
• Olivia Langdon Clemens (1845–1904), wife of Samuel Langhorne Clemens (Mark Twain)
• Orion Clemens (1825–1897), brother of Samuel Langhorne Clemens (Mark Twain)
• Paul Clemens (born 1988), American baseball player
• Pierre Clemens (born 1970) Belgian visual artist
• Roger Clemens (born 1962), American baseball player
• Mark Twain, pen name of Samuel Langhorne Clemens (1835–1910), American 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
• William Clemens (film director) (1905–1980), American film director

Given name

• Clemens (rapper), (born 1979), real name Clemens Legolas Telling, Danish rapper, singer, music writer, actor
• Clemens (impostor) (died c. 15 AD), ancient Roman
• Clemens Alexandrinus (Clement of Alexandria, c. 150–c. 215), Christian theologian
• 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
• Clemens Maria Hofbauer (1751–1820), patron saint of Vienna
• Clemens Holzmeister (1886–1983), Austrian architect
• Clemens Kalischer (1921–2018), German-American photographer
• Clemens von Ketteler (1853–1900), German diplomat
• Clemens Klotz (1886–1969), German architect
• Clemens Krauss (1893–1954), Austrian conductor
• Clemens Rehbein (born 1992), German musician
• 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
• Clemens Wenceslaus of Saxony (1739–1812), Saxon prince, Archbishop-Elector of Trier, Prince-Bishop of Freising, Prince-Bishop of Regensburg and Prince-Bishop of Augsburg
• Clemens Westerhof (born 1940), Dutch football manager
• Clemens Wilmenrod (1906–1967), German television cook
• Clemens Winkler (1838–1904), German chemist

Fictional characters

• Dr. Jonathan Clemens, a character in the 1992 film Alien 3 played by the British Actor Charles Dance
• Clemens, a slave in the Cambridge Latin Course