Food insecurity contributes to various stress-related health problems and previous research found that its association with mental illness is stronger in more affluent countries. We hypothesised that this pattern is a function of relative deprivation whereby the severity of individual food insecurity relative to others in a reference group determines its associations with mental health and wellbeing after differences in absolute food insecurity are controlled for. Using survey data from the Gallup World Poll collected in 160 countries and a measure of relative deprivation (Yitzhaki index), we found that relative food insecurity-based on national or regional reference groups-related to more mental health symptoms, lower positive wellbeing an...