William Oscar Mulkey (July 27, 1871 – June 30, 1943) was a U.S. Representative from Alabama.

Born in Brundidge, Alabama, Mulkey attended the public schools and graduated from State Normal College, Troy, Alabama, (now Troy University) in 1892.

He was admitted to the bar in 1893 and commenced practice in Troy, Alabama, in 1894.

Mulkey was elected as a Democrat to the Sixty-third Congress to fill the vacancy caused by the resignation of Henry D. Clayton and served from June 29, 1914, to March 3, 1915.

This article incorporates public domain material from the Biographical Directory of the United States Congress