Rabbi Hershel Schachter (born July 28, 1941) is an American Orthodox rabbi, posek (religious law authority) and rosh yeshiva (dean) at Rabbi Isaac Elchanan Theological Seminary (RIETS), part of Yeshiva University (YU) in New York City. Schachter is an halakhic (Jewish law) advisor for the Orthodox Union, and has rendered notable decisions in a number of contemporary topic areas.