Previous research has produced mixed evidence on the success of green crowdfunding campaigns. We investigate whether country-level environmental institutions help explain these inconsistencies by moderating backers’ responses. While such institutions may enhance campaign legitimacy, they can also reduce the perceived urgency to contribute by offering alternative support channels. Analyzing a large Kickstarter dataset with machine learning, we find that green campaigns are less likely to succeed, particularly in countries with stronger environmental institutions. Post-hoc analyses point to a crowding-out effect of institutional support, which dampens individual backing, and suggest that omitted variable bias may partly account for prior conflicting results.