William Washington Jones Kelly (April 7, 1814 – September 8, 1878) was the first Lieutenant Governor of Florida.

William studied law and entered the Bar of Escambia County, Florida, on November 11, 1832.

In 1837, he served as a private with his father in a company of men that was formed in Pensacola to cross the bay and round up wayward Creek Indians, slated for removal to Oklahoma.

In 1851, he married Pauline Virginia Mitchell and was given bounty land in Santa Rosa County, Florida, for his service in the Mexican War.

In the 1860 census he owned 8 slaves (belonging to his late wife's estate and thus to his eldest daughter) and was the legal guardian of his brother, Frederick.

On Jan 21, 1861, Kelly resigned his commission in the U.S. Navy, one of the last allowed to do so before the outbreak of the American Civil War.

He was a delegate from Escambia County for the Republican Party for the 1865 Florida Constitutional Convention.