Objective: Examine the association between country-level gender social norms and (1) cardiovascular disease mortality rates; (2) female to male cardiovascular disease mortality ratios; and (3) life expectancy. Design: Ecological study with the country as the unit of analysis. Setting: Global, country-level data. Participants: Global population of countries with data available on gender social norms as measured by the Gender Social Norms Index (developed by the United Nations Development Programme). Main outcome measures: Country-level female and male age-standardised cardiovascular disease mortality rates, population age-standardised cardiovascular disease mortality rates, female to male cardiovascular disease mortality ratios, female and male life expectancy at birth. Outcome measure data were retrieved from the WHO and the Institute for Health Metrics and Evaluation. Multivariable linear regression models were fitted to explore the relationship between gender social norms and the outcome variables. Results: Higher levels of biased gender social norms, as measured by the Gender Social Norms Index, were associated with higher female, male and population cardiovascular disease mortality rates in the multivariable models (β 4.86, 95% CIs 3.18 to 6.54; β 5.28, 95% CIs 3.42 to 7.15; β 4.89, 95% CIs 3.18 to 6.60), and lower female and male life expectancy (β −0.07, 95% CIs −0.11 to −0.03; β −0.05, 95% CIs −0.10 to −0.01). These results included adjustment within the models for potentially confounding country-level factors including gross domestic product per capita, population mean years of schooling, physicians per 1000 population, year of Gender Social Norms Index data collection and maternal mortality ratio. Conclusions: Our analysis suggests that higher levels of biased gender social norms are associated with higher rates of population cardiovascular disease mortality and lower life expectancy for both sexes. Future research should explore this relationship further, to define its causal role and promote public health action.