Sir Brian O'Neill, 2nd Baronet (died 1694/1697) was an Irish landowner, barrister and judge. He was one of the Roman Catholic judges appointed by King James II of England in his effort to "Romanise" the Irish administration. As such he and his fellow Catholic judges have been treated harshly by historians. However William of Orange, after he overthrew his father-in-law James II, also made use of O'Neill's services for a time. He was the second of the O'Neill Baronets of Upper Claneboys.