This chapter analyses different urban dialects in the Arabic-speaking world, both old dialects and ones recently emerged as a result of inter-dialectal communication, linguistic accommodation and koineisation. The types of Arab cities are diverse, ranging from ancient cities to newly created ones. Further distinctions are those of size and demographic composition. The origin of cities’ populations and the urbanisation of society have been considered for understanding the formation of urban Arabic dialects. Due to all this, analysing contact and variation in urban contexts in the modern Arabic-speaking world is a complex and varied task, despite the fact that neither migration nor urbanisation are new phenomena.