Sir Turlough Lynagh O'Neill was an Irish Gaelic lord of Tír Eoghain in early modern Ireland. He was inaugurated upon Shane O’Neill’s death, becoming The O'Neill. From 1567 to 1595, Sir Turlough Luineach O'Neill was leader of the O'Neill clan, the most powerful family in Ulster, the northern province in Ireland. He was knighted in 1578.

Tír Eoghain, also known as Tyrone, was a kingdom and later earldom of Gaelic Ireland, comprising parts of present-day County Tyrone, County Armagh, County Londonderry and County Donegal (Raphoe). The kingdom represented the core homeland of the Cenél nEógain people of the Northern Uí Néill and although they ruled, there were smaller groups of other Gaels in the area. One part of the realm to the north-east broke away and expanded, becoming Clandeboye, ruled by a scion branch of the O'Neill dynasty. In one form or another, Tyrone existed for over a millennium. Its main capital was Dungannon, though kings were inaugurated at Tullyhogue Fort.