Hugh Gavelagh MacShane O'Neill (;[1] – January 1590) was a sixteenth-century Irishman of the O'Neill dynasty, specifically the MacShane branch. He was executed on the orders of his cousin the Earl of Tyrone.
Gavelagh was one of the many sons of Gaelic chief Shane O'Neill. Shane had captured[2] Catherine MacLean, wife of Calvagh O'Donnell, and made her his mistress.