The Moulouya River (Wadi Muluya, ) is a 520 km-long river in Morocco. Its sources are located in the Middle Atlas. It empties into the Mediterranean Sea near Saidia, in Northeast Morocco at about . Water level in the river often fluctuates. The river is used for irrigation. The Moulouya River formed the eastern border of the Rif Republic in the 1920's, a small part of Morocco containing important cities like Saïdia and Oujda lying to the east, between the Moulouya and the border with Algeria. Until 1956 the river also formed the eastern border of the Spanish Protectorate of Morocco.