William Henry Elder (1819 - 1904) was a U.S. archbishop. He served as the Roman Catholic Bishop of Cincinnati between 1883 and 1904.

William Henry Elder was born in Baltimore, Maryland, 22 March, 1819. His father (Basil Elder) was a descendant of William Elder an emigrant from England to America who came to America in colonial times. His mother was Elisabeth Miles (Snowden) Elder. In 1831 William Henry Elder entered Mt. St. Mary's College, Emmitsburg, Maryland, then presided over by the Rev. John Baptist Purcell, who afterwards became the second Bishop, and later the first Archbishop, of Cincinnati.

He was ordained a priest in Rome, 29 March, 1846. He became professor at the seminary at Emmitsburg, MD, a position he held until appointed Bishop of Natchez, for which he was consecrated in the cathedral of Baltimore, by Archbishop Kenrick, 3 May, 1857. In 1864 he was brought into prominence by his refusal to obey the order of the Federal troops at Natchez, to have certain prayers for the President of the United States recited publicly in the churches of his diocese. He was arrested, tried, and convicted; but the decision of the military court was reversed at Washington.

On 30 January, 1880, he was transferred to Cincinnati, becoming auxiliary bishop and coadjutor with the right of succession to Archbishop Purcell, whom he succeeded 4 July, 1883. Archbishop Elder was third Archbishop of Cincinnati and served the Archdiocese until his death in Cincinnati, 31 Oct., 1904

Elder High School, a Cincinnati, Ohio parochial school was named for Bishop Elder.