Yehuda Zvi Blum (Hebrew: יהודה צבי בלום; born 1931) is an Israeli professor of law and diplomat. In 1978–1984, Blum served as Israel Ambassador to the United Nations.
Yehuda Z. Blum was born in Bratislava, Czechoslovakia, in 1931 and observed his bar-mitzvah in the Bergen-Belsen concentration camp. He immigrated to British Mandate for Palestine in 1945. Blum earned his law degree from the University of London.
Blum joined the faculty of Hebrew University in 1965 and until retiring in 2001 occupied the Hersch Lauterpacht Chair in International Law there. He has served as a senior research scholar at the University of Michigan, and visiting professor in the law schools of the University of Texas, New York University, Tulane University, the USC Gould School of Law, and others. In 1968 he served as a UNESCO Fellow at the University of Sydney in Australia. He has written several books and published many scholarly articles on international legal problems in law journals in English, Hebrew and German. He is currently the law editor of the Encyclopaedia Hebraica.
In 1968, Blum worked for the United Nations Office of Legal Counsel. He was a member of Israeli delegation to 3rd UN Conference on the Law of the Sea in 1973. In 1976 he was part of the Israeli delegation to the 31st session of UN General Assembly. He served as Ambassador and Permanent Representative of Israel to the United Nations for six years, from 1978 to 1984.