["Agribusiness, Volume 42, Issue 2, Page 603-622, Spring 2026. ", "\nABSTRACT\nAchieving global food security requires sustainable transformations in agri‐food systems. Voluntary Sustainability Standards (VSS) such as Organic and Fairtrade aim to internalize certain social and environmental costs while promoting more equitable value distribution, improved market access, and sustainable production practices. Using farm‐level data from 392 mango producers in Peru, this study examines the determinants of certification adoption and evaluates the welfare effects of Organic and Fairtrade certifications, both individually and in combination. To address potential selection bias arising from both observable and unobservable factors, we employ a two‐stage Multinomial Endogenous Switching Regression (MESR) model. Our findings indicate that several factors significantly influence the adoption of certifications, including farmers' age, land tenure, access to transportation, land size, as well as crop and mango variety diversification. The results also show that Organic + Fairtrade double certification increases total household and food expenditures per adult equivalent among mango farmers. Disaggregating the effects by farm size further reveals a positive impact of Organic certification on food security among medium holders ( > 5 ha ≤ 16 ha), whereas Fairtrade certification enhances dietary diversity, particularly among marginal holders ( ≤ 2 ha) and smallholders ( > 2 ha ≤ 5 ha). These findings underscore the importance of taking into account scale effects in certification impact analysis and highlight the potential of Organic and Fairtrade schemes to improve household welfare and food security among mango producers in Peru.\n"]