An Leabhar Breac ("The Speckled Book"; Middle Irish: An Lebar Brec), now less commonly Leabhar Mór Dúna Doighre (The Great Book of Dun Doighre") or possibly erroneously, Leabhar Breac Mic Aodhagáin ("The Speckled Book of the MacEgans"), is a medieval Irish vellum manuscript containing Middle Irish and Hiberno-Latin writings. The manuscript is held in the library of the Royal Irish Academy in Dublin, where it is catalogued as RIA MS 23 P 16 or 1230.