Klein is the Dutch, German and Afrikaans word for "small", which came to be used as a surname, and thence passed into the names of places, concepts and discoveries associated with bearers of this surname.^[1]

• Aaron Klein (born 1979), senior adviser, chief strategist for Prime Minister Benjamin Netanyahu
• Arthur George Klein (1904–1968), United States Representative from New York
• Clayton Klein (born 1949), American politician in Oregon
• Elijah Klein (born 2000), American football player
• Ezra Klein (born 1984), American political writer
• Herb Klein (journalist) (1918–2009), American journalist, President Nixon's communications director
• Herb Klein (politician) (born 1930), American politician
• Herbert G. Klein (1918–2009), American political aide
• Jacob Theodor Klein ("Plinius Gedanensium") (1685–1759), Prussian jurist, historian, botanist, mathematician and diplomat
• Jacques Paul Klein (born 1939), French-born United States diplomat
• Joe Klein (born 1946), American writer for Time magazine
• Karsten Klein (born 1977), German politician
• Louis Klein (1759–1845), French politician and peer, General during the French Revolutionary and Napoleonic Wars
• Louis Christian Klein (1832–1900), German American politician in Wisconsin
• Norbert Klein (1956–2021), Dutch politician
• Ottilie Klein (born 1984), German politician
• Ralph Klein (1942–2013), Canadian politician
• Ron Klein (born 1957), American (Florida) politician
• Volkmar Klein (born 1960), German politician

• Klein (musician), recording artist, producer and singer from South London
• Alan Klein (born 1940), English singer and songwriter (New Vaudeville Band)
• Allen Klein (1931–2009), manager for the Beatles and Rolling Stones
• Barbara Lynn Klein (born 1950), American Playboy model, actress and singer known as Barbi Benton
• Carol Joan Klein (born 1942), American composer and singer-songwriter better known by her stage name Carol King
• Chris Klein (born 1979), American actor
• Dani Klein (born 1953), stage name of Danielle Schoovaerts (born 1953), Belgian singer and songwriter
• Elisabeth Klein (1911–2004), Hungarian-Danish pianist
• Ethan Klein (born 1985), American Youtuber
• Gary Klein (born 1942), songwriter, record producer, and co-writer of "(I Wanna Be) Bobby's Girl"
• Gene Klein (born 1949), American musician and member of the band Kiss, better known as "Gene Simmons"
• Gideon Klein (1919–1945), pianist and composer
• Iris Klein, German model and beauty queen crowned Miss International 1989
• Jesper Klein (1944–2011), Danish actor
• Jim Klein, American composer and songwriter
• Joey Klein, Canadian actor and film director
• Joost Klein (born 1997), Dutch hip hop artist
• Mannie Klein (1908–1994), American jazz trumpeter
• Marci Klein (born 1967), American Emmy-winning television producer
• Mark Klein (born 1993), American singer-songwriter
• Martina Klein (born 1976), Argentine model and TV presenter
• Oscar Klein (1930–2006), Austrian-born jazz trumpeter
• Robert Klein (born 1942), American stand-up comedian and actor

• A. M. Klein (Abraham Moses Klein, 1909–1972), Canadian poet
• Aaron J. Klein (1960–2016), Israeli author and journalist
• Augusta Klein (1866–1943), English author
• Bradley S. Klein (born 1954), American author, architecture editor for Golf Week magazine
• Charles Klein (1867–1915) London-born American playwright
• Chuck Klein (born 1947) American author
• Daniel Martin Klein (born 1939), American author
• Ernest Klein (1899 – February 4, 1983), Canadian linguist, author, and rabbi
• Gérard Klein (born 1937), French science fiction writer
• Hannelore Klein (born 1927), German-born American linguist and write known as Laureen Nussbaum
• Joe Klein (born 1946), American journalist and novelist (Primary Colors)
• Josef K. Klein (1896–1971), Bulgarian poet of Austrian origin known by the pseudonym Gustav Heinse
• Julius Leopold Klein (1810–1876), Hungarian dramatist
• Marlon Klein (born 1957), German world music and fusion musician and producer
• Naomi Klein (born 1970), Canadian author and activist
• Nathan Klein (1923–2004), Ukrainian-born Israeli poet known as Natan Yonatan
• Robin Klein (born 1936), Australian author of children's books
• T. E. D. Klein (born 1947), American horror writer and editor

• Aaron E. Klein (1930–1998), American historian of science
• Abel Klein (born 1945), American mathematician
• Christine Klein, German physician
• Dan Klein, American computer scientist
• Daniel Klein (grammarian) (Lithuanian: Danielius Kleinas; 1609–1666), German-Lithuanian pastor and grammarian
• Daniel B. Klein (born 1962), American economist
• Emanuel Edward Klein (1844–1925), British bacteriologist
• Esther Klein (married name Esther Szekeres; 1910–2005), Hungarian–Australian mathematician
• Etienne Klein (born 1958), French physicist and philosopher of science
• Felix Klein (1849–1925), German mathematician
• Fritz Klein (1888–1945), German Nazi physician and war criminal
• Fritz Klein (sex researcher) (1932–2006), American sex researcher
• Gary A. Klein (born 1944), American research psychologist
• George Klein (inventor) (1904–1992), Canadian inventor
• Heinz Klein (1940–2008), American sociologist
• Jacob Theodor Klein (1685–1759), Prussian botanist
• Jan Klein (born 1936), Czech-American immunologist
• Lawrence Klein (1920–2013), American economist
• Leo S. Klein, or Leo Klejn (1927-2019), Russian Jewish archaeologist, anthropologist and philologist
• Luella Klein (–2019), American obstetrician-gynecologist and professor
• Martin J. Klein (1924–2009), American science historian of physics
• Marty Klein (born 1950), American sex therapist
• Melanie Klein (1882–1960), British psychotherapist
• Oskar Klein (1894–1977), Swedish physicist
• Richard Klein (paleoanthropologist) (born 1941), American paleoanthropologist
• Sabra Klein, American microbiologist
• Samuel Klein (1886–1940), Hungarian-born rabbi, historian and historical geographer
• Wilhelm Klein (1850–1924), Hungarian-Austrian archeologist
• Willem Klein (1912–1986), Dutch mathematician and famous mental calculator
• Wolfgang Klein (linguist) (born 1946), German linguist

• Aart Klein (1909–2001), Dutch photographer
• Anna Klein (painter) (1883–1941), German landscape, animal and genre painter
• Franz Klein (1779–1840), Viennese sculptor, who created a famous bust of Beethoven
• Fred Klein (1898–1990), Dutch painter active in France; father of Yves Klein
• Mary-Austin Klein (born 1964), American artist
• Roman Klein (1858–1924), Russian architect
• Todd Klein (born 1951), comic book letterer
• Vilhelm Klein (1835–1913). Danish architect
• William Klein (1926–2022), American-born French photographer and filmmaker
• Yves Klein (1928–1962), French painter, son of Fred Klein

• Ernest Klein (1899–1983), Canadian linguist and rabbi
• Félix Klein (1862–1953), French priest and theologian
• Isaac Klein (1905–1979), American rabbi
• Menashe Klein (1924–2011), American rabbi
• Norbert Klein (1866–1933), Grand Master of the Teutonic Knights

• Anne Klein (1923–1974), American fashion designer
• Bill Klein (businessman) (born c. 1948), American businessman and poker player
• Calvin Klein (fashion designer) (born 1942), American fashion designer
• David Klein (1946), Invented Jelly Belly Jelly Beans.
• David Klein (1935–2021), governor, Bank of Israel
• Fernando Heydrich Klein (1827–1903) German businessman, politician, engineer and sculptor
• Gary Klein creator of Klein bicycles.
• Jonathan Klein (CNN), president of the American television news network CNN
• Jonathan Klein (Getty Images) (born 1960), founder of Getty Images
• Leonardo Farkas Klein (born 1967), Chilean businessman
• Mathias Klein, founder of Klein Tools
• Michel Klein (born 1958), French fashion designer
• Robin Klein (venture capitalist) (born 1947), British entrepreneur and investor
• Samuel Klein (1923–2014), Polish-Brazilian business magnate

• Abraham Klein (referee) (born 1934), Israeli football referee
• Ágnes Keleti (born 1921), born Klein, Hungarian-Israeli Olympic champion artistic gymnast
• Brydan Klein (born 1989), Australian-born British tennis player
• Chris Klein (soccer) (born 1976), American soccer player
• Chuck Klein (1904–1958), American baseball player
• Collin Klein (born 1989), American football player
• Dede Klein (1910–1966), Canadian ice hockey player
• Dieter Klein (born 1988), South African cricketer
• Elijah Klein (born 2000), American football player
• Ernest Klein (1910–1990), Austrian-British chess master and author
• Erwin Klein (d. 1992), American table tennis player
• Frederick C Klein (born 1938), American sportswriter
• Hanna Klein, German athlete
• Herbert Klein (swimmer) (1923–2001), German swimmer
• Jackie Klein (born 1937), American artistic gymnast
• Joe Klein (baseball executive) (1942–2017), American baseball executive
• Kevin Klein (born 1984), Canadian ice hockey player
• Kristin Klein (born 1970), American volleyball player (1959–1993)
• Ľudovít Klein (born 1995), Slovak mixed martial artist
• Marlin Klein (born 2002), German-American football player
• Martin Klein (footballer), Czech international footballer
• Martin Klein (wrestler) (1884–1947), Estonian wrestler
• Michael Klein (footballer) (1959–1993), Romanian international footballer
• Noeki Klein (born 1983), Dutch water polo player
• Perry Klein (born 1971), American football quarterback in the National Football League who played for the Atlanta Falcons
• Ralph Klein (basketball) (1931–2008), Israeli basketball player and coach
• Raul Klein (1932–1998), Brazilian footballer
• Roelof Klein (1877–1960), Dutch rower
• Siegmund Klein (1902–1987), American bodybuilder
• Will Klein (baseball) (born 1999), American baseball player
• Wolfgang Klein (1941–2017), German athlete

• Carol Klein (born 1945), British gardening broadcaster and writer
• Fritz Klein (1888–1945), German Nazi doctor hanged for war crimes
• Gerda Weissmann Klein (1924–2022), Holocaust survivor
• Hans Klein (1891–1944), German Luftwaffe Major-General
• Johannes Klein (died 1926), German First World War flying ace
• Mark Klein (fl. 2006), American whistleblower and former AT&T technician
• Suzy Klein (born 1975), British music and arts broadcaster

• Cline (surname)
• Clyne (surname)
• Klein (disambiguation)
• Kline (surname)