This empirical study of fifty-two environmental conflict resolution (ECR) processes is based on an evaluation framework that specifies key conditions and factors that contribute to ECR outcomes. Data were collected on a range of ECR processes and applications. This article reports on findings from a multilevel modeling analysis that focuses on three primary outcomes: reaching agreement, the quality of agreement, and improved working relationships among parties. Effective engagement of parties is identified as a major contributor to all three outcomes. Other key factors that operate directly and indirectly through effective engagement are involvement of appropriate parties, the skills and practices of ECR mediators and facilitators, and incorporation of relevant and high-quality information. Findings generally support the ECR evaluation framework.