This article provides a review of scholarly approaches to assessing the impact of certification standards for sustainability. While we observe that some theoretical advances have afforded a better understanding of the potential impacts of adopting such standards, we also find that progress has been constrained due to a strong emphasis on assessing impact via linear causal pathways. This linear focus on the net effects for single stakeholders, such as farmers and producers, local communities and ecosystems, falls short of adequately capturing the broader impact of certifications across social and ecological dimensions. Inspired by theories on complex systems thinking, we present a framework based on a systems-based impact logic that better captures and assesses the impacts of certification standards within broader social-ecological systems. Our framework can be used as a heuristic to design impact-related studies and assess the impact of certification standards across disciplinary vantage points and empirical contexts.