Orsisius (kwa Kimisri: Oresiesis-Heru-sa Ast; alifariki 380) alikuwa Mkristo wa Misri, ambaye alimfuata Pakomi jangwani akamsaidia kutunga kanuni ya kwanza kwa ajili ya jumuia za wamonaki. Kiongozi wa monasteri katika kisiwa cha Tabenna, alipofariki Pakomi (348) alichaguliwa kushika nafasi yake, lakini alimuachia Theodori. Baada ya huyo pia kufariki (380 hivi), ndipo tu alipokubali kwa shauri la Atanasi wa Aleksandria. Tangu kale anaheshimiwa kama mtakatifu. Sikukuu yake huadhimishwa tarehe 15 Juni. Jeromu alitafsiri baadhi ya maandishi yake "Orsisius". Catholic Encyclopedia. New York: Robert Appleton Company. 1913. http://www.newadvent.org/cathen/11328a.htm. Watakatifu wa Agano la Kale Orodha ya Watakatifu Wakristo Orodha ya Watakatifu wa Afrika Orodha ya Watakatifu Wafransisko Mababu wa jangwani https://catholicsaints.info/saint-orsisius Gennadius, De viris illustribus, IX, aliandika: Oresiesis the monk, a colleague of Pachomius and Theodore, perfectly learned in the Scriptures, composed a Divinely savoured book containing instruction for all monastic discipline, in which nearly the whole Old and New Testaments are explained in short dissertations in as far as they affect monks; and shortly before his death he gave this book to his brethren as his testament.