This chapter describes Arabic prescriptivism by drawing on examples from academic conferences, television discussion programs, style guides, and teaching materials. Arabic prescriptivism differs form that of many other modern languages in being conditioned by diglossia and a considerable historical distance to the codification of the language. Arabic prescriptivism has two main strands (following Curzan 2014): standardizing and stylist prescriptivism. The first is related to the diglossic language situation and is concerned with the widespread use of non-standard varieties. The standard variety is in this strand taken to be essential to nationalist and religious identities and is portrayed as being under existential threat by non-standard varieties of Arabic. The second strand is concerned with regulating the use of alternative forms within the standard variety, basing its judgments exclusively on works of the classical heritage. Both these strands of prescriptivism have considerable real-world effects, most importantly in education.