Based on a multilevel analysis, this study explores the impact of classes and schools on the mathematics performance of 4th grade elementary students in two cities of the Democratic Republic of the Congo. It reveals that, out of the total variance, 71%, 16% and 13% are situated at student, classroom and school levels, respectively. The study further shows that beyond the effect of individual characteristics, class characteristics explain 2.9% of the variance situated at class level and 3.4% of the variance located at school level. However, only the pretest class average and class size are significantly associated with student performance. The study finally shows that if school characteristics explain 1.5% of the variance situated at school level, the principal’s experience stands for the unique significant predictor of students’ performance.