Mansur ibn al-Mahdi
| Mansur ibn al-Mahdi  منصور بن المهدي | |
|---|---|
| Governor of Syria | |
| In office 809–810 | |
| Monarchs | Harun al-Rashid, al-Amin | 
| Preceded by | Ali ibn al-Hasan ibn Qahtaba (807–809) | 
| Succeeded by | Ahmad ibn Sa'id al-Harashi (810) then Sulayman ibn Abi Ja'far (810) | 
| Personal details | |
| Born | Khurasan or Baghdad, Abbasid Caliphate | 
| Died | 810s Baghdad, Abbasid Caliphate | 
| Parents | 
 | 
| Relatives | Sulayman (uncle) | 
| Full name | Mansur ibn Muhammad al-Mahdi | 
| Religion | Islam | 
Mansur ibn al-Mahdi (Arabic: منصور بن المهدي) was an Abbasid prince, son of Abbasid caliph al-Mahdi, brother of caliph al-Hadi and Harun al-Rashid. Mansur was governor of Syria during his nephew caliph al-Amin's reign.