William Joshua Phelps (March 2, 1808 – February 20, 1883) was an American politician from Connecticut. Settling in Peoria County, Illinois in 1834, Phelps became a prosperous miner was elected to the Illinois House of Representatives. Phelps' house was the namesake of Elmwood and Elmwood Township, Illinois. Descended from the colonist William Phelps, William J. Phelps is the father of William E. Phelps.