As a starting point, this paper offers a theoretical discussion of a number of widely used yet diversely conceived concepts: (standard) language ideology, identity, agency, and indexicality. Using these concepts, we analyze a number of illustrative interview extracts from a corpus of sociolinguistic interviews with Flemish primary and secondary school teachers. Our goal is twofold. First, we discuss how Flemish teachers perceive (the importance of) Standard Dutch and other, nonstandard varieties of Dutch. Second, we show how these perceptions discursively shape teacher identities of authenticity, authority, and professionalism.