Engaging students in their learning, and within their learning community, is a key goal of educators. However, ongoing discussions about its nature, conceptualization, and measurement have led to a diffusion of the concept’s understanding, and ability to apply it within both research and practice. This chapter draws on theoretical and empirical primary and secondary ODDE research, and provides an overview of student engagement and disengagement, particularly as they relate to educational technology. The four dimensions of behavioral, affective/emotional, cognitive, and social (dis-)engagement are presented, alongside example indicators. In addition, a bioecological model of student engagement is explored with explicit links to digital learning. The chapter concludes by providing open questions and directions for future research, including further emphasis and exploration needed on the role of social engagement in ODDE contexts, as well as disengagement as a separate construct.