Adhamh Ó Cianáin (died 1373) was an Irish historian and genealogist.
Described in his obituary as "a learned historian" and "a canon" of Lisgoole, "having secured victory of deamon and world".
A member of the Ó Cianáin learned family of Fermanagh, Adhamh studied under Seán Mór Ó Dubhagáin; it was from the latter's book that Adhamh wrote Leabhar Adhamh Ó Cianain ('The Book of Adhamh Ó Cianáin') according to a colophon, whilst another states "Adhamh O Cianan ro sgribh in leabhar sa do fen/Adhamh Ó Cianáin wrote this book for himself".