Problem gambling represents a major global challenge with serious economic, social, and psychological consequences. While risk factors have been extensively investigated, protective factors remain less explored. Among them, financial literacy has been suggested as a potential buffer, improving decision-making and reducing financial anxiety, yet evidence of its protective role in gambling disorder is still scarce. Grounded in the Health Belief Model, this study aims to investigate whether higher financial literacy can mitigate problem gambling by influencing perceived severity, benefits, barriers, and self-efficacy. The purpose is to clarify the relationship between financial literacy and gambling behaviours, to test the predictive value of Health Belief Model constructs, and to compare Italian and UK contexts, where educational policies on financial literacy differ substantially. The research adopts a quantitative cross-cultural design using a Computer-Assisted Web Interviewing survey administered to two representative samples of 1,000 adult gamblers each. The questionnaire integrates validated measures of financial literacy, financial anxiety, and gambling severity, together with HBM-based items specifically developed for this study. Data collection is ongoing and results are not yet available, but it is expected that higher financial literacy will be associated with lower levels of problem gambling, partly mediated by reduced financial anxiety and stronger self-efficacy. Differences are also anticipated between the UK, where financial literacy has been embedded in the school curriculum since 2014, and Italy, where such education is less structured. By addressing these questions, the study seeks to provide evidence for an explanatory model of the protective role of financial literacy, with important implications for designing culturally informed preventive interventions.