Baron O'Neill, of Shane's Castle in the County of Antrim, is a title in the Peerage of the United Kingdom.

[1] It was created in 1868 for the musical composer The Reverend William O'Neill.

Lord O'Neill was succeeded by his eldest son, the second Baron.

Arthur O'Neill, represented Antrim Mid in the House of Commons as a Conservative from 1910 until 1914, when he was killed in action during the First World War, the first MP to die in the conflict.

The family seat is Shane's Castle, near Randalstown, County Antrim.