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

William Oscar Mulkey
Member of the U.S. House of Representatives from Alabama's 3rd district
In office June 29, 1914 – March 3, 1915
Preceded by	Henry D. Clayton
Succeeded by	Henry B. Steagall
Member of the Alabama House of Representatives
In office 1911
Personal details
Born	William Oscar Mulkey (1871-07-27)July 27, 1871 Brundidge, Alabama
Died	June 30, 1943(1943-06-30) (aged 71) Geneva, Alabama
Political party	Democratic

Born in Brundidge, Alabama, Mulkey attended the public schools and graduated from State Normal College, Troy, Alabama, (now Troy University) in 1892. He studied law. He was admitted to the bar in 1893 and commenced practice in Troy, Alabama, in 1894. He served as member of the State constitutional convention in 1901. He served in the State house of representatives in 1911.

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. He was not a candidate for renomination in 1914. He resumed the practice of law. He died in Geneva, Alabama, June 30, 1943. He was interred in Geneva Cemetery.