Background: Anxiety and depressive disorders can be chronic and disabling, and are associated with poor outcomes. Whilst there are effective treatments, access to these is variable and only a fraction of those in need receive treatment. Aims: The primary aim was to investigate sociodemographic correlates of lifetime treatment access and unpick the relationships between socioeconomic features and treatment inequalities. As such, we aimed to identify groups at greatest risk of never accessing treatment and targets for intervention. Methods: We tested for sociodemographic factors associated with treatment access in UK Biobank participants with lifetime generalised anxiety or major depressive disorder, performing multivariable logistic regressions on two binary outcomes: treatment-seeking (n=33,704) and treatment receipt (n=28,940). Results: Treatment access was less likely in those who were male, from a UK ethnic minority background and who self-medicated with alcohol or drugs. Treatment access was more likely in those who reported use of self-help strategies, with lower income (<£30,000) and greater neighbourhood deprivation, as well as those with a university degree. Conclusion: This work on lifetime treatment seeking and receipt replicates known correlates of treatment receipt during time of treatment need. Our focus on treatment-seeking and receipt highlights two targets for improving treatment access. More work is required to understand the psychosocial barriers to treatment, which mediate the associations observed here.