This chapter proposes a novel perspective on language policy as a form of public policy, highlighting some of the epistemological implications of this approach and discussing its linkages with more standard approaches originating in applied linguistics. After introducing the relevance of interdisciplinarity and complexity as defining features of this enterprise, it focuses on the connections between principles of public policy on the one hand, and the specificities of language policy on the other hand. To this end, this chapter develops an entirely novel typology of the main dimensions of language policy (type, domain, sphere, tier, welfare, target, causation and instrument), with which the latter may be extensively described and characterised. These dimensions bring to the fore the importance of jointly considering the micro, meso and macro levels at which language policies necessarily unfold. Given the extreme complexity of practically any language policy, and the associated difficulty of establishing the full range of effects (including both advantages and drawbacks) of alternative policy choices, analysts often need to fall back on pragmatic solutions in the selection and design process. Accordingly, this chapter emphasizes the role of plausibility as a valid criterion for evaluating such effects.