Fiannamail (d. 680), son of Máel-tuile and overking of Leinster, belonged to the dynasty of Uí Máil. Although his great-uncle Crimthann Cualann (qv) had died in 633 as overking of Leinster, Fiannamail's immediate predecessor in the Uí Máil kingship is not clear. According to the Leinster king-lists, he was preceded as provincial ruler by the Uí Dúnlainge dynast Fáelán (qv) son of Colmán, although this claim is not strongly supported by the annals.
Fiannamail is accorded a reign of thirteen years as overking, which implies an accession date of c.666/7. Striving to maintain his dynasty's claims in the south midlands against Uí Néill expansion, Fiannamail took the offensive but was not successful in re-establishing Leinster dominance in Brega. In 677 he was defeated near Lagore (Co. Meath) by the Uí Néill overking, Fínshnechtae Fledach (qv). Three years later, after a defeat at Aífe or Selgg (apparently near the Glen of Imaal, Co. Wicklow) inflicted by Uí Chennselaig, Fiannamail was slain by a kinsman named Fochsechán. A note in the genealogies (Rawl. B. 502, 125a 25) maintains that this assassination was instigated by Fínshnechtae Fledach, which is not improbable.
There is no record that Fiannamail left descendants. With the fortunes of Uí Máil failing, an Uí Dúnlainge rival, Bran Mút (d. 693) son of Conall, took the kingship of Leinster, but a son of Fiannamail's first cousin, Cellach Cualann (qv), emerged to reclaim the provincial dignity for his dynasty.