Throughout their history, dictionaries have been understood as sources of authority, whether that authority has been claimed by their makers or imputed by their audiences. In English-language contexts, that authority has taken various guises – moral, colonial, and legal, among others. Such authority rests, in part, on the linking of words, word forms, and grammatical structures to judgments about speakers, communities, and social relations. While those judgments have largely been aligned with codifying and maintaining a perceived “standard,” dictionaries have been sites of resistance, too. This chapter explores both assertions of authority and resistance. Given the long history of dictionaries and their substantial variety, the chapter adopts a case-study-like approach. It uses examples to explore how dictionaries have on the one hand upheld the civic, cultural, and social order, and on the other celebrated the linguistic practices and lexical innovations of marginalized communities and stigmatized varieties.