Over the past decade, private food safety and quality standards have become focal points in the supply chain management of large retailers, reshaping governance patterns in global agrifood chains. In this article, I analyze the relationship between private collective standards and the governance of agrifood markets, using the EUREPGAP/GLOBALGAP standard as a vantage point. I discuss the impact of this standard on the organization of supply chains of fresh vegetables in the Kenyan horticulture industry, focusing on the supply chain relationships and practices among exporters and smallholder farmers. In so doing, I seek to highlight the often-contested nature of the implementation of standards in social fields that are marked by different and distributed principles of evaluating quality, production processes, and legitimate actions in the marketplace. I also reconstruct the challenges and opportunities that exporters and farmers are facing with regard to the implementation of and compliance with standards. Finally, I elaborate on the scope for action that producers and policymakers have under these structures to retain sectoral competitiveness in a global economy of qualities.