Multinational enterprises are often accused of taking advantage of lax environmental regulations in developing countries. However, no quantitative analysis of the impact of doing business in nations of different income levels on environmental corporate social responsibility has been done prior to this study. Incorporating institutional factors in our approach, we argue that endoisomorphic and exoisomorphic pressures relating to ECSR impact MNEs differently according to the MNEs' level of activity in low-, lower-middle-, upper-middle-, and high-income nations. We predict and, using data (...) from 113 companies, find that selling in poorer nations is positively associated with increased levels of ECSR. Our research suggests that MNEs may not be participating in a “race to the bottom” but may instead be responding to global institutional pressure by exceeding local norms for environmental stewardship. Alternative interpretations of our findings are discussed. (shrink)