| John IV Megas Komnenos | |
|---|---|
| Emperor and autocrat of all the east and Perateia | |
 Coin of John IV of Trebizond | |
| Emperor of Trebizond | |
| Reign | 26 April 1429 – April 1460 |
| Predecessor | Alexios IV |
| Successor | Alexios V |
| Co-emperor | Alexander (c. 1451 – c. 1459) |
| Born | Before 1404 |
| Died | April 1460 |
| Spouse | Bagrationi |
| Issue | Theodora Megale Komnene |
| Dynasty | Komnenos |
| Father | Alexios IV Megas Komnenos |
| Mother | Theodora Kantakouzene |
John IV Megas Komnenos (Greek: Ιωάννης Μέγας Κομνηνός, Iōannēs Megas Komnēnos) (died April 1460) was Emperor of Trebizond from 1429 until his death. He was a son of Emperor Alexios IV of Trebizond and Theodora Kantakouzene.