Student engagement, while widely recognized as both important to outcomes of higher education institutions and critical to student learning, is still missing a unifying model addressing students both inside and outside of the classroom. This mixed-methods paper will explore the existing models of student engagement and propose a model which better supports analysis from multiple perspectives. This model was validated within the context of Vietnamese higher education. The results indicate that student engagement, both in-class and out-of-class, can be modeled through the four sub-components of emotional, cognitive, participatory, and agentic engagement. Having these common elements allows analysis vertically, through these four dimensions, or horizontally, across two contexts, providing greater flexibility for future investigations.