The significance of private standards and associated local level initiatives in agri-food value chains are increasingly recognised. However whilst issues related to compliance and impact at the smallholder or worker level have frequently been analysed, the governance implications in terms of how private standards affect national level institutions, public, private and non-governmental, have had less attention. This article applies an extended value chain framework for critical analysis of Private Standards Initiatives (PSIs) in agrifood chains, drawing on primary research on PSIs (...) operating in Kenyan horticulture (Horticulture Ethical Business Initiative and KenyaGAP). The paper explores the legislative, executive and judicial aspects of governance in these southern PSIs highlighting how different stakeholders shape debates and act with agency. It is argued that governance is exercised ‘beyond the vertical’ in that one can identify wider horizontal processes of governance, including how the scope of key debates is constructed (especially in legislative governance) but analysis of executive governance emphasises the dominant role of the lead buyers. (shrink)