Ó Maoilriain (anglicised as Ryan, Mulryan, or Mulrain) is an Irish Gaelic clan based in what is today County Tipperary and County Limerick.

The clan claims descent from Cathair Mór of the Laighin, but they first appear in the historical record in the 15th century in the kingdom of Thomond.

John O'Donovan claims they are distinct from the Ryan clan which ruled Uí Dróna in what is today County Carlow.

Owney derived its name from one Uaithne Ó Maoilriain.

According to historian C. Thomas Cairney, the O'Mulryans were one of the chiefly families of the Feara Cualann who in turn were a tribe from the Dumnonii or Laigin who were the third wave of Celts to settle in Ireland during the first century BC.