Online learning has increased in prominence across all levels of education, despite reported learner engagement being lower online than during in-person learning. Most learner engagement research and frameworks have focused on in-person learning environments but new frameworks and strategies for online learner engagement are emerging. In this article, we integrate scholarship from educational technology with scholarship from educational psychology and the learning sciences to argue for a reconceptualization of online learner engagement that considers both critical dimensions of learner engagement and the environmental affordances that influence them. We review literature on cognitive, affective, and behavioral engagement, translating it to online contexts. We introduce five research themes and accompanying frameworks from online learning research that have shaped understanding of learner engagement in online learning environments (i.e., engagement through communication, interaction, presence, collaboration, and community). With this new perspective that synthesizes the dimensions of learner engagement and online environmental affordances, we expand online learner engagement scholarship. Finally, leveraging this reconceptualization, we share an exemplar framework and strategies for supporting online learner engagement followed by recommendations for future research and practice.