Conservation organizations promoting sustainable seafood have had greater success when chefs are empowered as agents of change in favour of sustainable seafood. Peru is experiencing a gastronomic revolution with seafood at its core, and Peruvian top chefs are being approached by conservation organizations to become environmental advocates. Within this context we characterize the factors that influence chefs’ behaviours regarding sustainable seafood. A total of 52 Peruvian top chefs were surveyed using the Knowledge, Attitudes and Practices Framework, complemented by a focus group with a subset of the surveyed population. Our results suggest that, regardless of their age or academic background, chefs are aware of the negative consequences that human activities have on the ocean and believe that restaurants have an obligation to become part of the solution by promoting the use of sustainable seafood. Nonetheless, three factors limit chefs’ understanding of key concepts and prevent them from fully internalizing the environmental consequences of their actions in restaurants: (1) sustainability is a new topic for them, particularly for older chefs; (2) the fish species commonly used at restaurants are poorly regulated, and (3) chefs are risk averse to actions that could result in profit loss. Additionally, the structure of the seafood supply chain further limits chefs’ capacity to act sustainably, even if they are aware of the need to change their behaviour. Recommendations are provided for future conservation campaigns advocating use of sustainable seafood, some of which have now been implemented.