While environmental management is an important topic in supply chain management, there is little theoretical understanding of how firm practices (supervisory support, rewards, and training) relate to employee engagement in environmental behaviors. Drawing upon behavioral research literature, the purpose of our article is to use organizational support theory to develop a model of how employee perceptions of management practices influence employee engagement in environmental behaviors such as participating in environmental management activities, promoting environmental initiatives, and proposing innovative environmental practices. The theoretical model was evaluated using a sample of supply chain management employees employed by a major retailer and support was found for all of the hypothesized relationships except those entailing rewards. Study findings demonstrate the importance of employee perceptions in advancing employee-level involvement in environmental behaviors and how organizations can modify their internal infrastructures to champion environmental behaviors through their effects on employee perceptions of support for the environment and commitment to the environment. Additionally, the research illustrates how an extant behavioral theory, organizational support theory, can profitably be modified and adopted to explain behavior in the field of supply chain management.