Businesses play a central role in addressing environmental sustainability, and one of their most difficult internal decisions is whether to commit to environmentally responsible purchasing. This study develops a theoretical framework to explain what drives purchasing professionals in Sweden’s food retail industry to engage in environmentally responsible purchasing. The framework is tested using survey data from 573 purchasing managers. The findings show that all proposed hypotheses are supported, indicating that moral beliefs, together with situational and organizational influences, play a key role in individuals’ environmentally responsible decision making within organizations. The study also offers guidance on how companies can promote environmentally responsible purchasing by influencing employees and, over time, strengthening their organizational culture.