Drawing from research on strategic management and environmental psychology, this study investigates the role of independent directors' and CEOs' values in promoting sustainable development. We propose that their values may interactively shape directors' focus on environmental sustainability. We test our propositions with survey data from 176 directors and matching CEOs. Our results confirm that there is a significant positive relationship between directors' biospheric values and their environmental sustainability focus, which is further amplified by CEO egoistic values. In contrast to our expectations—and regardless of CEO values—directors' egoistic values appear to be unrelated to their environmental sustainability focus. As such, this research points to the importance of director and CEO values acting as substitutes rather than complements in shaping directors' environmental sustainability focus. Taken together, this study highlights the importance of considering both director and CEO values in promoting environmental policy at the top of the organization.