Yekusiel Yehudah Halberstam (January 10, 1905 - June 18, 1994) was an Orthodox rabbi and the founding rebbe of the Sanz-Klausenberg Hasidic dynasty. His was known for his personal righteousness, kindness toward others, and Torah wisdom that positively influenced whole communities before, during and after the Holocaust, making him a natural leader, mentor, and father figure for thousands of Jews of all ages.