Viscount Valentia is a title in the Peerage of Ireland. It has been created twice. The first creation came in 1621 for Henry Power. A year later, his kinsman Sir Francis Annesley, 1st Baronet, was given a "reversionary grant" of the viscountcy, which stated that on Power's death Annesley would be created Viscount Valentia. Annesley, a member of an influential Anglo-Irish family which descended from Newport Pagnell in the County of Buckinghamshire, was a favourite of James I, who granted him land in Ireland, notably the fort of Mountnorris in County Armagh. He was knighted in 1616, created a baronet, of Newport Pagnell in the County of Buckingham, in the Baronetage of Ireland in 1620 and Baron Mountnorris, of Mountnorris in the County of Armagh, in 1628.

The Peerage of Ireland consists of those titles of nobility created by the English monarchs in their capacity as Lord or King of Ireland, or later by monarchs of the United Kingdom of Great Britain and Ireland. It is one of the five divisions of Peerages in the United Kingdom. The creation of such titles came to an end in the 19th century. The ranks of the Irish peerage are duke, marquess, earl, viscount and baron. As of 2016, there were 135 titles in the Peerage of Ireland extant: two dukedoms, ten marquessates, 43 earldoms, 28 viscountcies, and 52 baronies. However, these titles have no official recognition in the Republic of Ireland, with Article 40.2 of the Constitution of Ireland forbidding the state conferring titles of nobility and stating that an Irish citizen may not accept titles of nobility or honour except with the prior approval of the Irish government.