As teachers and students have taken more active roles in assessment practices, our field has begun to pay more attention to classroom-based assessment (CBA). As a result, we have gained a better understanding of CBA principles but we have also become aware of challenges, particularly in applying traditional assessment concepts such as reliability and validity to the classroom context. In this article I continue the argument that viewing assessment through a sociocultural perspective will help us broaden our understanding of classroom learning environments and rethink traditional assessment concepts for CBA.