This article documents and compares the most prominent sustainability assessment programs for individual organisations in viticulture worldwide. Certification and engagement processes for membership uptake; benefits; motives; inhibiting factors; and desirable reporting system features of viticultural sustainability programs, are all considered. Case-study results are derived from nine sustainability programs; 14 focus groups with 83 CEOs, Chief Viticulturists or Winemakers from wine grape production organizations from five countries (Australia, Chile, New Zealand, South Africa and the United States); 12 semi-structured interviews with managers either currently or formerly in charge of the sustainability programs; researcher observations; and analysis of documents. Programs were categorized by their distinct program assessment methods: process-based, best practice-based, indicator-based and criterion-based. We found that programs have been created to increase growers' sustainability, mainly through the direct and indirect education they receive and promote, and the economic benefit to their business caused by overall improvement of their operations. The main finding from this study is that the success of each of these programs is largely due to the people driving the programs OPEN ACCESS Sustainability 2014, 6 2032 (program managers, innovative growers and/or early adopters) and the way these people communicate and engage with their stakeholders and peers.