Selso wa Armagh (pia: Cellach, Selestino; Ireland, 1080 hivi – Ardpatrick, Munster, 1 Aprili 1129) alikuwa askofu mkuu wa Armagh na Ireland yote, wakati Ukristo katika kisiwa hicho ulikuwa umepoa. Alipochaguliwa kuwa askofu ingawa bado mlei, kama ilivyomtokea babu yake, alichangia sana urekebisho wa Kanisa la huko katika karne ya 12 na kupatanisha watawala. Bernardo wa Clairvaux alimsifu kama mtu mwema na mcha Mungu. Tangu kale anaheshimiwa na Wakatoliki kama mtakatifu. Sikukuu yake huadhimishwa tarehe 1 Aprili. Watakatifu wa Agano la Kale Orodha ya Watakatifu Wakristo Orodha ya Watakatifu wa Afrika Orodha ya Watakatifu Wafransisko Ó Fiaich (1969), p. 94 http://www.santiebeati.it/dettaglio/48100 Martyrologium Romanum Annals of Innisfallen, CELT: Corpus of Electronic Texts, 2000, retrieved 2010-03-19  Annals of the Four Masters, CELT: Corpus of Electronic Texts, 2002, retrieved 2010-03-19  Annals of Ulster AD 431–1201, CELT: Corpus of Electronic Texts, 2003, retrieved 2010-03-19  Chronicon Scotorum, CELT: Corpus of Electronic Texts, 2003, retrieved 2010-03-19  Byrne, Francis John (2001). Irish Kings and High-Kings, 2, Dublin: Four Courts Press.