Rav Moses Feinstein (Hebrew: משה פיינשטיין‎; March 3, 1895 – March 23, 1986) was a Lithuanian Orthodox rabbi, scholar, and posek (an authoritative adjudicator of questions related to Jewish law), who was world-renowned for his expertise in Halakha and was regarded by many as the de facto supreme halakhic authority for Orthodox Jewry of North America.