This study aimed to explore relationships between being an 'affected other' (AO) and an individual's own gambling, health risk behaviours, financial problems, poor general health, and low mental wellbeing. A cross-sectional survey using representative and supplementary convenience samples was undertaken with 1234 residents of a British Island aged 16 + years. Being an AO was measured as having a partner or relative who has been gambling regularly in the past 12 months. PGSI was used to assess gambling severity. Health risk behaviours included: poor diet, low physical activity, daily smoking, and binge drinking. Other measures included experiencing financial problems, poor general health, and low mental wellbeing. Analyses were performed using χ and binary logistic regressions. 11.0% of participants were AOs. AOs were more likely to gamble at at-risk/problem-gambling levels and experience financial problems compared to those who were not affected others. The significant relationship between being an AO and low mental wellbeing was mediated by experiencing financial problems. The relationship between being an AO and engaging in two or more health risk behaviours was no longer significant after controlling for sociodemographics and an individual's own gambling. The relationship between being an AO and poor general health was no longer significant after controlling for sociodemographics, health risk behaviours and an individual's own gambling. AOs experienced risks to health and wellbeing, with findings not limited to AOs specifically with a relationship to an individual with problem-gambling. Therefore, support for AOs should be more widely available, aiming to address AOs' needs holistically.