Over the last three decades, transnational certification standards have proliferated to fill perceived ‘governance gaps’ in developing countries. Transnational non-governmental organisations and private standards-setting agencies have developed standards that cover a vast range of areas such as labour rights, social justice and environmental protection. As a form of private transnational regulation, certification standards travel through transnational production networks that link lead firms in developed countries with supplier firms in developing countries. This article draws on a case study about coffee certification to challenge the conventional understanding of transnational certification as a contractual conduit that transfers encoded certification standards from senders to receivers. It shows how transnational certification standards interact with, and remake local regulatory landscapes as they pass through. This interaction between global and local knowledge compels us to see transnational standards as a protean, highly localised regulatory process rather than stable universal norms. The article concludes that transnational certification does not function like an integrated ‘joined-up’ process and it is better understood as a mode of polycentric regulation that decentres and fragments transnational norms and standards.