Pachad Yitzchok (or Pachad Yitschak) may refer to:
Hebrew of "Fear of Isaac", a Biblical reference in Genesis 31:42 (an allusion to God) The writings or person of Rabbi Yitzchok Hutner (1906–1980) The writings or person of Rabbi Yitzchok Friedman (1850–1917), First Rebbe of Boyan The Talmudic responsa of Rabbi Yitzhok Mordechai Tzadok Marszalkowicz (circa 1780-circa 1840) son-in-law of Rabbi Akiva Eiger (born Gunsz) (1761-1837) responsa prepared for publication by his son Rabbi Shmuel Marszalkowicz eventually published 1998 by Rabbi Samuel Udwin (died 2024 Jerusalem) Yeshiva Pachad Yitzchok A rabbinic encyclopedia authored by Isaac Lampronti (1679-1756)