Based on data from international surveys measuring learning (TIMSS), this article focuses on the analysis of the academic performance Moroccan students. The results of the econometric model show that the students' characteristics, their family environment and school context are key determinants of these performances. The study also shows that the Moroccan educational system is segmented: urban versus rural and public versus private. This double duality illustrates clearly that the Moroccan education system is a juxtaposition of a "categories" rather than a "unified" market.