Kleiner (Hebrew: קליינר) is a German and Jewish surname, meaning "smaller":
Alfred Kleiner, Swiss physicistBruce Kleiner, American mathematicianKrista Arrieta Kleiner, Filipino-American TV actress/singer and hostDick Kleiner, Hollywood columnistEugene Kleiner, Silicon Valley venture capitalistEugène-Louis Kleiner, Roman Catholic bishopIsrael Kleiner (biochemist) (1885-1966), biochemistIsrael Kleiner (mathematician), Canadian mathematician, professor at McGill UniversityJohn J. Kleiner, US Congressman from IndianaMichael Kleiner, Israeli politicianMorris Kleiner, American professor of public affairsSergio Kleiner, Argentine soap opera star