Research has suggested ePortfolios reveal and support students' metacognition, that is, their awareness, tracking, and evaluation of their learning over time. However, due to the wide variety of purposes and audiences for ePortfolios, it has been unclear whether there might be common criteria for identifying and assessing metacognition in ePortfolios across varied contexts. The purpose of this study was to identify evidence of metacognition across ePortfolios of three distinct populations of students: traditional-age undergraduates, graduate Education students, and adults returning to school to complete a bachelor's degree. We set out to explore if and how ePortfolios could support these different learners' growth as reflective, intentional learners and professionals. Through a qualitative coding process, we identified four key metacognition markers across students' ePortfolios in these three populations. We conclude students can be guided to engage in metacognition in concrete ways through thoughtful assignment design and assessment process, no matter their context.