Immigrants’ children constitute a population on average less advantaged than other pupils. However, their success at junior high school is very unequal, varying according to the characteristics of their family background: when they are compared one with another, it is always when the family has a greater cultural capital that their chances of success are highest. In addition, their success is not unrelated to the number of siblings: when there are more than three children, school trajectories and level of achievement deteriorate as the number of siblings increases. Given comparable family and social characteristics, the educational achievements of immigrants’ children varies according to the parents’ country of origin. But this disparity in achievement is due essentially to the educational excellence of children from South-East Asia who substantially outperform other pupils. However, the success of immigrants’ children does not appear to be strongly linked with the time their mother has spent in France or her level of linguistic integration. Pupils born abroad and who have therefore themselves experienced migration come in sixth place for their achievements in French and maths where they are less confident than other immigrants’ children, but they catch up in junior high school. Girls perform better than boys in French and they are less likely to repeat a year. This is clearly seen from the time they enter junior high school, and is strengthened considerably in the following years. Girls also catch up in maths, where their achievements had previously been poorer.