In this article, we present key aspects of a research project entitled "Students' Cultural Diversity and School Efficacy: A Repertory of Best Practice in Compulsory Learning Centers." First, we present our concept of cultural diversity and a reflection regarding "best school practices" and the notion of "student achievement at school." In the second part, we analyze two practices which may seem quite different from each other: learning communities and a program of attention to diversity, which illustrate several ways of adopting an intercultural approach. The repertory of good practices mentioned can serve as an insightful resource for teachers. (Contains 8 notes and 1 figure.)