Kagan is a surname (Kaganovich variation). "Kagan" is a primarily Russian-Jewish surname which could be derived from the surname "Kahan" and is likely related to "Khagan". It is a state designation (kingdom) and a royal title (ruler, King of kings) used by the Turkic (e.g. Gokturk Khaganate) Khazar people (e.g. Khazar Khaganate on the territory of present-day Russia) or Mongolian title. It could also be related to Cohen (in Russian the consonant h is replaced with the consonant g).
Notable people with the Kagan surname include:
Bernhard Kagan (1866-1932), German chess player, writer, publisher, editor, and organizer
Daryn Kagan (born 1963), former American newscaster
Donald Kagan (born 1932), Yale historian specializing in ancient Greece (Frederick and Robert Kagan's father)
Elena Kagan, (born 1960) dean of Harvard Law School, U.S. Solicitor General (under President Obama), and Associate Justice of the U.S. Supreme Court
Frederick Kagan (born 1970), professor of military history (Robert Kagan's brother)
Henri Kagan, French chemist
Helena Kagan, (1889-1978) pioneer-pediatrician of Israel
Janet Kagan (1946–2008), author
Jeremy Kagan (born 1945), American television director
Jerome Kagan (born 1929), children developmental psychology
Joseph Kagan, Baron Kagan (1915–1995), British industrialist
Kimberly Kagan (born 1972), military historian (Frederick Kagan's wife)
Oleg Kagan (1946–1990), Russian violinist
Robert Kagan (born 1958), American historian and political commentator (Frederick Kagan's brother)
Robert A. Kagan, a law professor and author of a book on adversarial legalism
Shelly Kagan, philosopher and ethicist at Yale University
Shimon Kagan (born 1942), Israeli chess master
Veniamin Kagan (1869–1953), Russian mathematician
Vladimir Kagan (1927–2016), German furniture designer
Yisrael Meir Kagan (1838–1933), Polish-born rabbi, halakhist, and ethicist
