Dialectologists have documented a great deal of regional variation across varieties of the Arabic language. This chapter takes dialectology as its foundation, highlighting how the application of sociolinguistic theory and method to the study of Arabic can refine our understanding of variation across different dialects of Arabic. This is accomplished first through an overview of dialectological research that focuses on regional variation in a selection of linguistic features that have been widely studied. This overview is then built upon to show how sociolinguistic research on these features, and in these communities, enriches earlier findings from Arabic dialectology.