Language assessment literacy (LAL), an increasingly prominent research topic, has generated substantial literature in language testing and assessment. Thus far, there seems to be few comprehensive reviews on this research topic. The current scoping study reviewed a total of 81 papers by synthesising LAL studies published from 2008 to 2020. It addressed research questions concerning (1) the overall trend and progress, (2) the research foci and (3) characteristics of implications of LAL research for language teacher education and professional development. The review found that there was an upward trend in LAL studies, which were conducted predominantly in the Asia-Pacific region, Europe and the Middle East, and that most studies employed qualitative over quantitative and mixed-methods designs. An overwhelming majority of studies focused on language teachers, especially EFL teachers, while few were conducted from the perspectives of learners, policy makers, language testers, teacher educators and other stakeholders. The review also discovered that most studies researched stakeholders' LAL levels, needs and development, overlooking LAL developmental trajectories, localised LAL components, the development of LAL measures, perceptions of LAL and LAL impact. Three characteristics were identified from implications of LAL studies as contributions to language teacher education and professional development. Based on the findings, some guidelines were suggested for future research.