Learner engagement correlates with important educational outcomes, including academic achievement and satisfaction. Although research is already exploring learner engagement in blended contexts, no theoretical framework guides inquiry or practice, and little consistency or specificity exists in engagement definitions and operationalizations. Developing definitions, models, and measures of the factors that indicate learner engagement is important to establishing whether changes in instructional methods (facilitators) result in improved engagement (measured via indicators). This article reviews the existing literature on learner engagement and identifies constructs most relevant to learning in general and blended learning in particular. The authors present a possible conceptual framework for engagement that includes cognitive and emotional indicators, offering examples of research measuring these engagement indicators in technology-mediated learning contexts. The authors suggest future studies to test the framework, which they believe will support advances in blended learning engagement research that is increasingly real time, minimally intrusive, and maximally generalizable across subject matter contexts.