Ayoun al Atrous (also known as Aioun el Atrouss) () is a town in southern Mauritania. It is located at around . It is the capital of Hodh El Gharbi region.
The city is served by the Aioun el Atrouss Airport, north-west of the city. The town is located in the southern area of the Aoukar, a former lake basin.
Ayoun al Atrous was one of the stops in the 2007 Dakar Rally.