William Andrew Leonard (July 15, 1848 - September 21, 1930) was an American author and prelate of the Episcopal Church, who served as the fourth Bishop of Ohio from 1889 till 1930.

His grandfather was Stephen B. Leonard, who was a member of the United States House of Representatives from New York.

He spent part of his early youth in Mount Vernon, Ohio, where he worked as a clerk in a clothing store owned by a relative.

He then studied at St Stephens College in Annandale-on-Hudson, New York from where he graduated with a Bachelor of Arts in 1866.

He subsequently served as chaplain of the Twenty Third Regiment of the New York National Guard from 1876 till 1880.