Background: Previous research has documented how people living on low incomes in the United Kingdom (UK) and internationally experience various forms of poverty stigma. The purpose of this study was to quantitatively examine how experiences of poverty stigma are associated with mental health outcomes. Methods: An online, cross-sectional survey was conducted with 1,000 adults living in predominantly low- and middle-income households in the UK. The survey included a questionnaire designed to measure participants’ experiences of different forms of poverty stigma, as well as measures of anxiety, depression and mental well-being. Findings: Exploratory and confirmatory factor analyses of the poverty stigma questionnaire supported a two-factor solution. One factor reflected participants’ experiences of being mistreated and judged unfairly by other people because they live on low income (received stigma) and the other factor reflected participants’ perceptions of how people living in poverty are treated by media outlets, public services and politicians (perceived structural stigma). Both received and perceived structural stigma were independently associated with anxiety, depression and mental well-being and these relationships persisted after controlling for socioeconomic indicators. There was also evidence that received stigma and perceived structural stigma partially mediated the relationships between financial hardship and mental health outcomes. Discussion: Experiences of received and perceived structural poverty stigma are both associated with mental health and well-being. This suggests that addressing interpersonal and structural forms of poverty stigma may help to narrow socioeconomic inequalities in mental health.