Oliver S. Marshall (September 24, 1850 – May 19, 1934) was an American politician serving as a member of the West Virginia Senate from 1st District in three terms from 1897 to 1901, 1905 to 1909, and 1913 to 1917.

He was the great grandson of Aaron Marshall, a pioneer settler about 1760 of what is now Hancock County, West Virginia.

In 1896, Oliver S. Marshall was elected to the West Virginia State Senate from the First Senatorial District.

During his term he presided over Senate proceedings that led to the passage of bills that incorporated West Virginia banks and savings institutions, established a procedure for West Virginia public institutions to report to the Legislature, and reorganized the process for the Legislature to consider appropriations bills.

[1][3] His house at New Cumberland, West Virginia was listed on the National Register of Historic Places in 2001.