Abstract: Firms are under pressure to reduce greenhouse gas emissions not only from their own operations but across the entire value chain. However, this requires supplier adoption of climate-friendly practices, which can be difficult when suppliers perceive such practices as risky or detrimental to their economic well-being. We employ a field experiment to study strategies for engaging suppliers to overcome this challenge. In a research collaboration with a Fortune 500 firm seeking to decarbonize its agricultural supply chain, we examine the effectiveness of complementing its training on climate-friendly practices for its supplier farmers with customized agricultural support that created immediate and visible value for these farmers. We tested two interventions that differed in the nature and extent of this support: a lower investment intervention in which existing field officers provided customized advice on the crop the farmers produced for the firm, and a higher investment intervention in which expert agronomists were additionally brought in to provide customized advice for a broader range of agricultural matters. Relative to a control group that was simply exposed to training about the new practices, both interventions improved the farmers’ adoption of the new practices. The higher investment intervention produced greater environmental impact, even for emissions reduction per dollar, while also improving farmer retention in the program. Our post-experiment survey data analysis and field interviews suggest that these treatment effects were driven at least in part by the farmers’ perceptions of how committed the firm was to their economic well-being and to forging a long-term relationship.