Musa Ag Amastan (1867–1920) was the Chief (Amenokal) of the Kel Ahaggar Tuareg from 1905 to 1920.

There are indications that Moussa's life did undergo a considerable change when he was about 30 years old (that is, c. 1897) in the form of an enhanced religiosity, which can be attributed to the spiritual mentorship of Bay al-Kunti [1][2] who resided in Téleya in the Adrar des Ifoghas.

[2] In 1901 Musa ag Amastan was part of the Kel Ahaggar coalition leading a rezzu (invasion) against the Berabich of Azawad submitted to the French authorities in Timbuktu.

Led officially by the captain Niéger and accompanied by the commander Laperrine, his journey then took the name of "Mission Touareg".

Antonello Padovano wrote and directed the film "The Four Doors of the Desert" based on Moussa Ag Amastan life and his love for Dassine Oult Yemma and his friendship with Father Charles de Foucauld.