William T. Haskell was an American politician and a member of the United States House of Representatives for Tennessee's 11th congressional district. He was born in Murfreesboro, Tennessee on July 21, 1818. He was privately tutored, he attended the public schools of Murfreesboro, and he attended the University of Nashville in Nashville, Tennessee. He was a soldier in the Seminole War in 1836. During the Mexican-American War, he served in the First Brigade, Second Regiment of the Tennessee Volunteers. He worked as a lawyer in private practice.
In 1840 and 1841, William T. Haskell served in the Tennessee House of Representatives. He was elected as a Whig to the Thirtieth Congress. He served from March 4, 1847 to March 3, 1849. He died in Hopkinsville, Kentucky on March 12, 1859. He was interred in Riverside Cemetery in Jackson, Tennessee. He was the nephew of fellow congressman Charles Ready.