Mauricius Ó Leaáin was Bishop of Kilmacduagh, Ireland, from 1254 to 1284. Ó Leaáin (O'Leane, Lane, Linnane) is associated with the Oranmore–Clarenbridge area of County Galway. He was the first of three men of the surname to become bishop of Kilmacduagh.
Ó Leaáin was elected before 15 May 1254 and received possession of the temporalities after that date. He died before 16 January 1284.