ObjectivesTo assess primary impact of selective Licensing (SL), an area-based intervention in the private rented housing market, on individual self-reported anxiety and neighbourhood mental health (MHI—Mental Healthcare Index) and secondary impacts on antisocial behaviour (ASB), population turnover and self-reported well-being.DesignDifference-in-difference (DiD) was used to evaluate effects of SL schemes initiated 2012–2018. 921 intervention areas (lower super output areas) were matched 3:1 using propensity scores derived from sociodemographic and housing variables (N=3.684 including controls). Average treatment effect on treated (ATT) was calculated for multiple time period DiD in area-level analyses. Canonical DiD was used for individual-level analysis by year of treatment initiation while adjusting for age, sex, native birth and occupational class.SettingIntervention neighbourhoods and control areas in Greater London, UK, 2011–2019.ParticipantsWe sampled 4474 respondents renting privately in intervention areas (N=17 347 including controls) in Annual Population Survey and obtained area-level MHI population data.InterventionsPrivate landlords in SL areas must obtain a licence from the local authority, allow inspection and maintain minimum housing standards.ResultsATT after 5 years was significantly lower for MHI (−7.5%, 95% CI −5.6% to −8.8%) than controls. Antidepressant treatment days per population reduced by −5.4% (95% CI −3.7% to −7.3), mental health benefit receipt by −9.6% (95% CI −14% to −5.5%) and proportion with depression by −12% (95% CI −7.7% to −16.3%). ASB reduced by −15% (95% CI −21% to −8.2%). Population turnover increased by 26.5% (95% CI 22.1% to 30.8%). Sensitivity analysis suggests overlap with effects of London 2012 Olympic regeneration. No clear patterns were observed for self-reported anxiety.ConclusionsWe found associations between SL and reductions in area-based mental healthcare outcomes and ASB, while population turnover increased. A national evaluation of SL is feasible and necessary.