Rabbenu Gershom (also known as Gershom ben Judah) (c. 960 -1040? 1028?) was a Jewish Rabbenu who was the head of a Yeshiva in Mainz. He is commonly known as Rabbenu Gershom Meir Hagolah (Our teacher Gershom the light of the exile). He was the spiritual guider of the then fledging Ashkenazic Jewry. He was very influental in molding the Ashkenazic Jewry, whose population was dwindling at this time. During his lifetime, or because of him, Mainz became became a center of scholarship for many Jewish communities in Europe that had formerly been connected with the Babylonian yeshivas. Students came from all over Europe to study under him. His many students later dispersed among various communities inside and outside of Germany and helped spread Jewish learning. Rashi of Troyes (d.1105) said less than a century after his death "all members of the Ashkenazi dispora are students of his students". There has been suggestion that if Rabbenu Gershom never lived their may not have been something known as Ashkeanzic Judaism alive today as it is. As early as the 14th century Asher ben Jehiel wrote that Gershom's writtings were "such permanent fixtures that they may well have been handed down on Mount Sinai".

He is famous for his bans, which include the prohibition of polygamy, the prohibition of divorcing a woman against her will, and the prohibition of reading private mail. His bans were considered binding on all of Ashkenazic Jewry.