| Ali I علي الأول | |
| Succession: | Sultan of Morocco |
| Reign: | 836–849 |
| Full Name: | Ali Haidara bin Muhammad |
| Predecessor: | Muhammad bin Idris |
| Successor: | Yahya ibn Muhammad |
| Dynasty: | Idrisid |
| Father: | Muhammad bin Idris |
| Mother: | Roqiya bint Ismail al-Azadi |
| Birth Date: | 827 |
| Death Date: | 849 |
| Religion: | Islam |
Ali bin Muhammad bin Idris (Arabic: علي بن محمد بن إدريس) was the fourth Idrisid sultan of Morocco.
Ali was the son of Muhammad ibn Idris, whom he succeeded in March/April 836 at the age of nine. During his infancy, the chieftains of the Berber tribes acted as his regents. He proved an able ruler, who managed to stabilize and pacify the Idrisid realm after the troubled reign of his father. During his reign, Idrisid authority was strengthened and stretched from Basra to Tudgha. Some Idrisid troops reportedly also participated in the 846 Sack of Rome by Aghlabid raiders.
Ali died in January 849 at Fes and was succeeded by his brother Yahya I.