The field of language planning and policy (LPP) provides a rich array of research opportunities for applied linguists and social scientists. However, as a multidisciplinary field that seeks to understand, among other things, why some languages thrive whereas others are marginalized, LPP may appear quite theoretical and far removed from the lives of many English language teaching (ELT) practitioners. This is unfortunate, because ELT professionals-be they teachers, program developers, materials and textbook writers, administrators, consultants, or academics-are involved in one way or another in the processes of LPP. The purpose of this article is to unravel those processes and the role of ELT professionals in them for both theoretical and practical reasons: theoretical, because we believe there are principled ways to account for why particular events affect the status and vibrancy of languages and speech communities, and practical, because we believe there are ways to influence the outcome of social processes. In general, we find that the principle of linguistic self-determinism-the right to choose (within limits) what languages one will use and be educated in-is not only viable but desirable for LPP decision making because it both promotes social equity and fosters diversity. In this article, we examine how ELT professionals are already actively engaged in deciding language policies, how they promote policies reaffirming or opposing hierarchies of power that reflect entrenched historical and institutional beliefs (see Phillipson & Skutnabb-Kangas, this issue), and how they might affect changes in their local contexts.T he field of language planning and policy (LPP) has witnessed significant growth over the past 25 years. Scholars from a variety of disciplines, including linguistics, education, political science, history, policy studies, law, demography, and sociology, have continually broadened