Aim To test if being exposed to increased alcohol availability during adolescence is associated with an increased risk of receiving disability pension due to all-cause, alcohol use disorders and mental disorders. Design Register-based population-based study using a natural experiment setting, the alcohol policy change in Sweden (1967-68), with increased access to strong beer in a narrow time window and geographical area. The individuals exposed to the policy change were compared with non-exposed individuals living in the rest of Sweden, excluding a border area. Setting Sweden. Participants A total of 518810 individuals (70761 in the intervention group; 448049 in the control group) born 1948-1953, aged 14-20 years during the policy change. Measurements Date and diagnosis of the outcome variable of disability pension due to all-cause, alcohol use disorders and mental disorders were obtained from the Swedish National Social Insurance Agency database from 1971 to 2013. Individual and family level socio-demographic and health-related covariates, as well as a regional level covariate, were included. Findings Compared with the control group, adolescents exposed to the alcohol policy change were at an increased risk of receiving disability pension due to all-causes [hazard ratio (HR)=1.09, 95% confidence interval (CI)=1.07-1.11], alcohol use disorders (HR=1.17, 95% CI=1.05-1.30) and mental disorders (HR=1.19, 95% CI=1.15-1.23). Conclusion In Sweden, a natural experiment with a 43-year follow-up suggests that exposure to increased alcohol availability during adolescence is associated with an increased risk of receiving a disability pension due to all-cause, alcohol use disorder and mental disorder diagnoses.