In this review we closely follow the terms of reference set by RESOLV, with respect to the standards summarised below in Table 1.2, specifically: organic, GlobalGAP, Fairtrade, the Sustainable Agriculture Network standard (known as SAN, and sometimes referred to as the Rainforest Alliance (RA) standard), and Utz Certified), plus two newer standards – the Roundtable on Sustainable Palm Oil (RSPO) and the Roundtable on Responsible Soy (RTRS) standards. In most of the text the discussion focuses on the first five of these standards according to the availability of literature and the length of time that the standards have been in operation (RTRS only published its standard in June 2010 with its first certification in June 2011; RSPO Principles were agreed in 2005 followed by the criteria and indicators agreed 2007 and the first certification took place in 2008). So in section 1 we focus on the market for certified agricultural products exploring trends in supply and demand including reflections on how consumers and companies influence these trends. In section 2 we begin by discussing the evolving methodologies in use to assess impacts of standards and standards systems. Informed by this methodological understanding, we provide a summary of key findings from a variety of studies on particular standards or groups of standards in agriculture. In section 3 we consider the relative effectiveness of certification systems both in relation to each other and compared to other approaches to improving ‘sustainability performance’. Following this in section 4 we discuss communication of the standards to the public and public awareness of different standards. Here we explore the complex relationship with public regulation and also consider ways other than standards which may facilitate improvements. The concluding section summarises the key findings and presents our analysis of the gaps in knowledge that exist. We propose a research agenda that will enhance our understanding of standards and certification systems operating in agriculture, particularly with respect to how they meet their objectives and broader impacts, intended and unintended