Given the continued growth in the globalization of production, working conditions in global supply chains have come under increased scrutiny. Although there has been much debate about corporate codes of conduct and monitoring procedures, the question of how buyers influence their suppliers’ working conditions at the factory level remains poorly understood. Using a unique data set based on monitoring by the International Labour Organization (ILO) and original survey data collected in Cambodia’s garment sector, this study shows that the main channel linking buyers and supplier compliance performance is the nature of their relationships.