Corporate environmental performance has become a key focus of business leaders, policy makers, and scholars alike. Today, scholarship on environmental practice increasingly highlights how various aspects of corporate governance can influence environmental performance. However, the prior literature is inconclusive as to whether ownership by insiders (officers and directors) will have positive or negative environmental effects and whether insider voting control or equity control is more salient to environmental outcomes. This article leverages a unique empirical data set of dual-class firms, where (...) insiders have voting rights disproportionate to their equity rights, to shed light on this question. We find that, on average, dual-class firms underperform their single-class peers on environmental measures and that the discrepancy comes from dual-class firms where insiders have more voting control, relative to their equity stake. While small increases in voting control are associated with improved environmental performance, too much (relative to insiders’ equity stake) worsens firms’ environmental performance. Insider equity control alone has no impact on environmental outcomes. Our findings have important implications for agency theory and environmental scholarship by identifying contingencies on the impact of voting and equity-based incentives. This research casts doubt on the idea that providing insiders with significant voting control will aid environmental performance. (shrink)