As economic actors worldwide have entered Global Value Chains (GVCs), development opportunities within these systems have received increasing attention. However, upgrading following GVC participation is not straightforward. In this chapter, we conduct a systematic literature review answering what is the state of knowledge about the effect that distinct factors at various levels have on upgrading. We concentrate on the firm-level as these are the first agents to be subjects of upgrading, while explicitly considering the sustainable dimension of these paths too. We account for internal and external drivers, framing the latter from the perspective of governance. From our review, we elaborate an integrated framework to help advance both the GVC field and the research on sustainable development, as we reflect all the drivers of firm upgrading and the mechanisms employed and disentangle their effects on upgrading both as a process and an outcome.