Oum Er-Rbia (Arabic: أم الربيع, romanized: the mother of spring) is a large, long and high-throughput river in central Morocco.

It originates in the Middle Atlas and passes through the city of Khénifra, arriving at its mouth at the Atlantic Ocean at the port of Azemmour, located on its left bank.

According to scholars, the original Berber common name of the river is Wansifen and was only changed recently, circa 16th or 17th century, and a nearby village called Oum Rabia might have influenced this change.

[2] Oum Er-Rbia is fed by a large number of groundwater springs.

The area near its headwaters is called "The Forty Springs" as a result, although that is a poetic term rather than an exact count.