Eliezer Yehuda Waldenberg (Hebrew: הרב אליעזר יהודה וולדנברג), December 10, 1915 – November 21, 2006) was a rabbi, posek, and dayan in Jerusalem. He is known as a leading authority on medicine and Jewish law and referred to as the Tzitz Eliezer after his 21-volume halachic treatise covering a wide breadth of halacha, including Jewish medical ethics, and daily ritual issues from Shabbat to kashrut.