Louis Marcus (9 January 1880 Brooklyn – 6 July 1936 Salt Lake City) was, from 1931 to 1936, the mayor of Salt Lake City, the capital of Utah, and was also a prominent Idaho and Utah theater operator.
As of 2019, Marcus is the only Jewish mayor in the city's one hundred and seventy-two-year history.
He served as mayor until his death on July 6, 1936.