Louis Jacobs is a Masorti rabbi in England, former leader of Masorti Judaism (also known as Conservative Judaism) in the UK, best known as the central focus of what came to be known as "The Jacobs Affair".

Jacobs was ordained as an Orthodox Jewish rabbi, and taught at Jews' College, London. He taught Talmud and homiletics during the last years when Rabbi Isidore Epstein was principal. Jacobs was on the liberal side of Orthodox Judaism, and was interested in finding a synthesis that would accommodate Orthodox Jewish theology and modern day higher biblical criticism. Jacobs was especially concerned with how to reconcile modern day Orthodox Jewish faith with the documentary hypothesis. His ideas about the subject were published in a book entitled We Have Reason to Believe. It was the subject of some mild criticism at the time, but no great waves were made.

It was widely assumed that after Isidore Epstein's retirement he would be succeeded by Jacobs. When this assumption was translated into a definite invitation by the Board of Trustees to Jacobs to assume the position, the then Chief Rabbi of the United Kingdom, Israel Brodie, interdicted the appointment "because of his [Jacobs'] published views". This was a reference to Jacob's book We Have Reason to Believe.

One of Jacobs' friends at that time was the editor of the influential newspaper "The Jewish Chronicle". The newspaper took up the issue and turned it into a 'cause celebre'. Brodie countered, by informing the Board of Jacobs' synagogue that when his contract was up they might not renew it. They responded to this challenge by voting to leave the "United Synagogue", which was the umbrella organization for all London's mainstream orthodox synagogues.

The defecting congregation bought an existing synagogue building, established there an independent congregation and installed Jacobs as their incumbent rabbi - where he has been ever since.

Jacobs was influential in founding the Masorti Movement in England.