Many studies have examined the psychology of interest and interest development, with these studies spanning various fields such as educational psychology, personality development, and vocational guidance. However, the pragmatic benefit of being able to accurately measure interests has often overshadowed the broader potential benefits of research into interest development. Drawing from research across different fields, this article summarises the historical evolution of research into interest development, culminating with the four-phase model of interest development as advanced by Hidi and Renninger (2006). It proceeds to examine the impact of this research on the work of psychologists and counsellors in schools. Finally, this article concludes by problematising the current dominance of assessment services and the use of interest inventories, while exploring potential opportunities to better support student engagement through a broader understanding of interest development.