AbstractThe article evaluates the influence of pressure of 10 distinct types of stakeholders on the adoption of environmental strategies, with the special focus on the proactive environmental strategy (PES). The moderation effect of the company size on this relationship is investigated in depth. The existence of the relationship between stakeholder pressure and environmental strategies has been explored by numerous studies. The study adds significantly to this ongoing discussion as the moderation effect of the company size was explored scarcely so far in the literature. The results from the multinomial logistic regression models confirmed almost unanimously the effect of stakeholder pressure and the presence of the moderation. Positive, but nonlinear, direct and moderated effect of pressures of regulators, competitors, clients, NGOs, media, shareholders and employees on PES was discovered. In case of suppliers, consumers and top management, the pressure–PES relation was more complex. Also, large companies seem to be more resilient to pressures than the smaller ones when adopting PES.