Illegal fishing is a serious problem that threatens the sustainability of fisheries around the world. Historically, fisheries managers have attempted to increase the costs of illegal fishing through imposition of stricter sanctions and improvements to monitoring and enforcement programs. Non-monetary factors also influence illegal fishing behaviors, and failing to address them can undermine the efficacy of an otherwise well-designed fishery management system. Furthermore, in many of the world’s fisheries, strong and reliable monitoring and enforcement has proven to be an elusive goal. In such cases, interventions designed to address the social, moral, and cognitive drivers of illegal behavior can potentially supplement conventional deterrence methods. Building on insights from the behavioral sciences, we developed a process for designing interventions aimed at strengthening social incentives and psychological motivations for complying with fishery regulations. This process begins with an in-depth stakeholder characterization exercise. Potential interventions that may disrupt undesirable beliefs, norms, and modes of thinking, along with those that encourage behaviors that support the objectives of the fishery, are then developed. Experimental testing is conducted prior to piloting and, finally, scaling of the resulting intervention(s). We are currently applying this process in a catch share fishing community in the Upper Gulf of California, Mexico, where illegal fishing is a pervasive problem that jeopardizes the sustainability of the region’s fisheries, as well as the wellbeing of the community members who depend on them. The results of this research can inform management design to more effectively meet the environmental and social objectives of the region.