Mael Macduach (died 920) was King of Uí Fiachrach Aidhne.
Sub anno 920, the Annals of the Four Masters states Mael-micduach, lord of Aidhne, was slain by the foreigners.Annals of the Four Masters, AFM, 920.14 Aedh, son of Lonan O'Guaire, Tanist of Aidhne, died.AFM, 920.15
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