Using a Peircean theory of meaning, agency may be theorized in terms of flexibility and accountability, on the one hand, and knowledge and power, on the other. In this theory, residential agency, which is closest to notions such as "power" and "choice," is the degree to which one can control the expression of a sign, compose a sign-object relation, and commit to an interpretant of this sign-object relation. Representational agency, which is closest to notions such as "knowledge" and "consciousness," is the degree to which one can thematize a process, characterize a feature of this theme, and reason with this theme-character relation. Agency, as a kind of social and semiotic facility, is thereby theorized as multidimensional, graduated, and distributed. This theory allows one to analyze, as concomitant phenomena, the longue duree processes that underlie relatively perduring institutions and the real-time practices that support relatively fleeting interactions. Finally, it highlights the theoretical and empirical terrain shared by linguistic anthropology, science and technology studies, political economy, and critical theory.