| Church: | Church of Constantinople |
| Archbishop Of: | Ecumenical Patriarch of Constantinople |
| Term: | 9 May 1310 – 11 April 1314 |
| Predecessor: | Athanasius I of Constantinople |
| Successor: | John XIII of Constantinople |
| Death Date: | after 1314 |
Nephon I or Niphon of Cyzicus (Greek, Modern (1453-);: Νήφων; died after 1314) was the Ecumenical Patriarch of Constantinople from 1310 to 1314. From Veria, Greece. Nicephorus Gregoras claimed Nephon to be illiterate, a lover of luxury, and ill-suited for the position.[1] Due to his willingness to compromise, during his time as patriarch the Arsenite Schism was healed within the Byzantine Church. Nephon abdicated the throne after four years.