This chapter deals with linguistic variation and koinéization in the Maghreb. I briefly present some theoretical notions such as urban sociolinguistics, koiné and koinéization and macro-discriminant before focusing on the question of linguistic classification – not only through dialectological classification, but also through speakers’ self-categorization. The process of koinéization is illustrated through empirical data from the dialect of Rabat. The chapter also analyzes the conceptual trichotomy of old urban/rural/new urban, which seems to be functional in Maghrebi urban sociolinguistics as suggested by the situation in Rabat.