This paper sets out to examine the type of help, from parents to children and among siblings, in order to understand the educational involvement and strategies of large immigrant families. The first point consist in asking whether parental involvement is the same for all the children regardless of their birth rank and gender, the second point is about the help from siblings which remains a neglected dimension in the researches on family involvement in education. We used the "Trajectories and Origins" statistical survey and 42 follow-up interviews. We focus on children of immigrants from working classes who were either born in metropolitan France or who arrived there before age seven. Aged between 25 and 40 in 2008, the respondents had at least one immigrant parent from Algeria, Morocco, Tunisia, sub-Saharan Africa or Turkey; and a large majority has at least two siblings. The article highlights that parents invest more on eldest children in immigrant families as well as in French-origin ones; yet contrary to French-origin parents, immigrant parents from North Africa invest on their daughter's school career even more than in their sons' one. Siblings' help is especially important in immigrant families; they manage to compensate, at least partially, for the lack of parental help in school matters.