This paper analyses the liberalization process of the Moroccan mobile market since the beginning of the XXI century. Our database ranges from 2004 to the end of 2020. First, operators' market shares are presented and analyzed. Second, we build concentration indexes and other indicators of competitiveness. Finally, we conduct an econometric analysis to determine the extent to which regulatory measures, privatization, market structure and the population dimension determine market shares. Overall, we can argue that, although concentration remains high, the market has become more competitive since the liberalization process began. The statistical analysis and the econometric assessment show that the entrance of the third operator made the market more competitive. Indeed, there is evidence that operator companies competed to capture customers from each other during the period under study. These features suggest that mobile operators did not follow anticompetitive practices in order to restraint competition.