The 1970 United States Senate election in Mississippi was held on November 3, 1970. Incumbent Democratic U.S. Senator John C. Stennis won re-election to his fifth term, easily defeating independent candidate William Richard Thompson.
This race would be one of only two races where Stennis would face a general election challenger; as in his other races he had no general election opposition. Stennis won four times in the general election with every vote. (1952, 1958, 1964, and 1976.)