This paper explores the evolution of language policy and planning (LPP) as an area of research from the end of World War II to the present day. Based on analysis of the LPP literature, three types of factors are identified as having been instrumental in shaping the field. These factors – macro sociopolitical, epistemological, and strategic – individually and interactively have influenced the kinds of questions asked, methodologies adopted, and goals aspired to in LPP research. Research in LPP is divided into three historical phases: (1) decolonization, structuralism, and pragmatism; (2) the failure of modernization, critical sociolinguistics, and access; and (3) the new world order, postmodernism, and linguistic human rights. The article concludes with a discussion of current research trends and areas requiring further investigation.