Robert Humphreys (August 20, 1893 – December 31, 1977) was briefly a member of the United States Senate from Kentucky.

After service in World War I Humphreys worked as a registered pharmacist in the retail drug business in Mayfield, Kentucky and later at Frankfort, Kentucky.

During World War II he served as a captain in the Medical Corps, 1943–1945.

Then he resigned to accept appointment to the United States Senate on June 21, 1956, as a Democrat to fill the vacancy caused by the death of Alben Barkley.

Humphreys did not seek election to the Senate, opting instead to serve only for the brief time he was appointed.