Mael Fabhaill mac Cléirigh (died 887) was the King of Uí Fiachrach Aidhne in Ireland.
Mael Fabhaill was one of the last kings of Aidhne who did not use a surname. His son and successor, Tighearnach Ua Cleirigh, did so and was ancestor to the family of Ó Cléirigh.
Mael Fabhaill had a brother, Eidhean mac Cléirigh, who gave his name to the Ó hEidhin family of south County Galway.
References
Irish Kings and High-Kings, Francis John Byrne (2001), Dublin: Four Courts Press, Annals of Ulster at CELT: Corpus of Electronic Texts at University College Cork