In this article, we consider interest development and its implications for research and policy. We synthesise studies explaining the critical role of interest in learning, and explain the benefits of promoting the development of interest for all learners. We suggest that educators (whether these are parents, teachers, managers in Fortune 500 companies, museum docents, etc.) are uniquely positioned to support learners to develop interest. We review information about the historical roots, conceptualisation and measurement of interest, and current studies of interest. In concluding, we suggest that needed next steps for research include more targeted study of how educators can facilitate the development of interest. We further note that, given the importance of educators in promoting interest development, policies are needed that provide (1) preservice and practising educators with knowledge of how to effectively work with interest, and (2) opportunities for curriculum developers and policy makers to understand how interest can be supported to develop and why it is important.