William McCandless (September 29, 1834 – June 17, 1884) was an American military officer and politician from Pennsylvania.
He served in the Union Army during the American Civil War and commanded a regiment and then a brigade in the Pennsylvania Reserve Division.
He served as a Democratic member of the Pennsylvania State Senate for the 1st district from 1867 to 1868 and as the first Secretary of Internal Affairs of Pennsylvania from 1875 to 1879.