Athanasius I

Athanasius I may refer to:


 * Athanasius of Alexandria (c. 293 – 373), also called Pope Athanasius I of Alexandria, Christian theologian
 * Athanasius I Gammolo (died 631), Syriac Patriarch of Antioch
 * Athanasius I (bishop of Naples) (830–872)
 * Athanasius I of Constantinople (1230–1310), Ecumenical Patriarch of Constantinople