Oscar Sherman Gifford (October 20, 1842 – January 16, 1913) was an American lawyer of Canton, South Dakota.

He served six years in the United States House of Representatives, first as the non-voting delegate from the Dakota Territory, then as a full member of the House from South Dakota.

He served as a private in the Union during the American Civil War.

He was district attorney for Lincoln County, mayor of Canton, and a member of the State constitutional convention of South Dakota which convened at Sioux Falls on September 7, 1883.

Upon the admission of South Dakota as a state, it was allocated two seats in the U.S. House.