Fachtna is an Irish personal name and may refer to:
Ordered chronologically Fachtna Fáthach, 2nd-1st century BC high king of Ireland Fachtna of Kiltoom (), Irish saint Saint Fachanan or Fachtna, sixth century monastery founder and first bishop of Kilfenora Fachtna of Rosscarbery (died c. 600), Irish monastery founder and abbot Fachtna mac Folachtan (died 723), Abbot of Clonfert Fachtna Murphy (born 1947), Irish former Garda Commissioner Fachtna Ó hAllgaith (died 1232), Irish erenagh and benefactor