My paper investigates the methods developed and used by the French army and government to teach French to indigenous North African soldiers in the French Colonial Army. Although the main focus will be on the methods used in the years preceding and following World War I, some references will be made to methods developed all the way through WW2. The French colonial empire's growing need for more soldiers to be enlisted in its armies was met by an increased awareness of the importance of creating and publishing pedagogical materials allowing a better communication with native soldiers of Morocco, Algeria and Tunisia. By 1920, France had almost succeeded in imposing the French language as the sole language of communication within its armies. By doing so, the army contributed in a very significant way to the diffusion of French in North Africa. The paper uses materials and documents consulted during my research at the Bibliothèque Nationale de France during the summer of 2013. I will talk in details about some major textbooks developed by the military to meet the perceived needs of adult learners who lacked literacy in their first language. I will also investigate the implication of the language policy in the French colonial army and the role of teachers, translators and linguists in this endeavor. The success and limitations of these teaching methods will constitute the last part of the paper.