Oscar B. Marx (July 14, 1866 – November 23, 1923) was an American political figure, who was mayor of Detroit from 1913 to 1918.

[1][2] Marx attended the Detroit public schools and the German-American Seminary,[2] and spent much of his early life farming, but as Detroit and Hamtramck, Michigan grew, the encroaching cities swallowed the Marx farm.

[1] Marx's father Stephen sold the farm, giving him and his brothers several thousand dollars to start a business.

[1] Marx was friends with Robert Oakman and John Dodge, and the three men controlled the Republican Party in Southeast Michigan for much of the 1910s.

[4] Marx appointed James J. Couzens, the man who would become the next mayor, to take over the Detroit police force,[4] and in February of his final year in office Marx created a committee to oversee the feasibility of construction the Outer Drive bypass in the city.