René Samuel Cassin (born 5 October 1887 in Bayonne, France – died 20 February 1976 in Paris, France) was a French jurist, law professor and judge. The son of a French-Jewish merchant, he served as a soldier in World War I, and later went on to form the Union Fédérale, a leftist, pacifist Veterans organisation. He received the Nobel Peace Prize in 1968 for his work in drafting the Universal Declaration of Human Rights, adopted by the United Nations General Assembly on 10 December 1948. That same year, he was also awarded one of the UN's own Human Rights Prizes. René Cassin founded the French Institute of Administrative Sciences (IFSA) which was recognized as a public utility association.

As French delegate to the League of Nations from 1924 to 1938, Cassin pressed for progress on disarmament and in developing institutions to aid the resolution of international conflicts.

Working from a draft composed by Canadian scholar and professor of law, John Humphrey, he reduced the draft from 46 basic articles to 44. The Universal Declaration of Human Rights, as eventually adopted by the United Nations General Assembly on 10 December contained 30 human rights articles from the original draft.