William Robinson Sapp (March 4, 1804 – January 3, 1875) was a 19th Century American lawyer and politician who served two terms as a U.S. Representative from Ohio from 1853 to 1857.

He is the uncle of U.S. Representative William F. Sapp of Iowa.

Born at Cadiz, Ohio, Sapp moved to Knox County, Ohio, where he attended the public schools. He engaged in the mercantile business in Danville. He studied law. He was admitted to the bar in 1833 and commenced practice at Millersburg, Ohio.

He served as prosecuting attorney of Holmes County, Ohio. Presidential elector in 1844 for Clay/Frelinghuysen.^[1]

He moved to Mount Vernon, Ohio, in 1846.

Sapp was elected as a Whig to the Thirty-third Congress and reelected as an Opposition Party candidate to the Thirty-fourth Congress (March 4, 1853 – March 3, 1857). He was an unsuccessful candidate for reelection.

Assessor of internal revenue for the thirteenth district 1869-1872. He served as collector of internal revenue from 1872 until his death in Mount Vernon, Ohio, January 3, 1875. He was interred in Mound View Cemetery.

• United States Congress. "William R. Sapp (id: S000061)". Biographical Directory of the United States Congress.
•  This article incorporates public domain material from the Biographical Directory of the United States Congress

• Taylor, William Alexander; Taylor, Aubrey Clarence (1899). Ohio statesmen and annals of progress: from the year 1788 to the year 1900 ... Vol. 1. State of Ohio. p. 255.