| Conflict: | Siege of Nisibis |
| Partof: | the Roman–Persian wars |
| Date: | 252 AD |
| Place: | Nisibis (modern-day Nusaybin, Mardin, Turkey) |
| Territory: | Sasanians capture Nisibis.[1] |
| Result: | Sasanian victory[2] |
| Combatant1: | Roman Empire |
| Combatant2: | Sasanian Empire |
| Commander1: | Unknown |
| Commander2: | Shapur I |
| Strength1: | 2,000-5,000 Legionaries |
| Strength2: | Unknown |
The siege of Nisibis took place when the Sasanians under Shah Shapur I besieged the Roman city of Nisibis in 252. This marks the beginning of Shapur's I second invasion of the Roman empire which saw the first Sassanid invasion of Syria; the year of the invasion is debated as Shapur's inscription from Naqsh-e Rustam regarding his second campaign against Rome do not mention the city of Nisibis. But Syriac and Arabic sources, mainly the Chronicle of Seert and Al-Tabari, mention that Shapur took Nisibis in his eleventh regnal year; according to the historian David Stone Potter, this regnal year is 252. Another Syriac account, the Liber Caliphorum, from the eighth century, mentions the invasion of the city in 252.