Over the past 20 years, standards and certification have become the leading governance mechanism for determining what sustainability entails, how to measure it, and how to assess it. This system of sustainability standards has generally relied upon the third‐party certification (TPC) model to ensure that producers are complying with standards. Over the past ten to fifteen years, critiques of this model have emerged in both practitioner and academic circles that question the appropriateness of this model based on the type of knowledge that is privileged, the marginalisation of some actors, and the allocation of accountability to individual rather than collective actors. We draw upon case studies from Japan and Chile to examine the ways that participatory guarantee systems (PGS) institute practices for defining, measuring, and assessing sustainability that empower local actors – both producers and consumers. Our cases illustrate that expert and lay knowledges are both relevant and often have different strengths. We argue that PGS offer an alternative approach to sustainability governance, one that may be more democratic and hence, produce forms of sustainability that incorporate the lived experiences of people around the world.