The aim of this study is to shed light on the relationship between ISO 45001 adoption and firm performance. To explore the issue, we conduct an event study and a weighted least squares regression on a dataset of 157 publicly listed companies – operating in various countries and sectors – that have given public announcement of the attainment of the ISO 45001 certification. The results show that, when compared to non-adopters, ISO 45001-certified companies display better performance in terms of productivity and profitability, while no significant differences emerge for sales. The effects of ISO 45001 adoption are significantly influenced by industry- and company-related contextual factors. The study contributes to the academic literature by developing the first large-scale empirical investigation on the performance implications of ISO 45001. Furthermore, it informs managers that by ensuring healthy and safe workplaces companies can also achieve higher financial performance. (AU)