| Church: | Church of Constantinople |
| Archbishop Of: | Ecumenical Patriarch of Constantinople |
| Term: | 25 May 1265 – 14 September 1266 |
| Predecessor: | Arsenios Autoreianos |
| Successor: | Joseph I of Constantinople |
| Birth Date: | ? |
| Death Date: | 1289 |
Germanus III (Greek: Γερμανός; died 1289) was Ecumenical Patriarch of Constantinople (May 25, 1265 – September 14, 1266). He attended the Second Council of Lyon in 1272 as the representative of Michael VIII Palaiologos.