An insufficient supply of natural resources, pressure from various stakeholder groups (e.g., regulators, investors, employees, and consumers), and the move toward public disclosure of corporate environmental performance are among some of the driving forces that create significant pressure for organizations to become more environmentally sustainable (DuBois & DuBois, 2012). While more progress needs to be made, organizations around the world are increasingly implementing various pro-environmental initiatives (Ones & Dilchert, 2012; Zibarras & Coan, 2015). Yet, the success, and in some cases, the creation of many pro-environmental initiatives implemented at the firm level rely on employees' voluntary pro-environmental behavior (Boiral, Paillé, & Raineri, 2015; Unsworth, Dmitrieva, & Adriasola, 2013). As such, these behaviors are considered to be important contributors to corporate environmental sustainability (Robertson & Barling, 2015a) that have implications not only for the natural environment, but also for organizations (e.g., financial performance) and their members (e.g., leader effectiveness; employee job satisfaction; see Norton, Parker, Zacher, & Ashkanasy, 2015). In recent years, scholars have recognized the importance of employees' pro-environmental behavior such that a growing body of research has begun to emerge (Norton, Parker, et al., 2015). Importantly, researchers have focused on identifying the predictors of them. Within this literature, leadership has been identified as a significant antecedent. In particular, several studies have shown that a specific leadership style, namely, environmentally specific transformational leadership (ETFL) matters in the context of influencing workplace pro-environmental behavior (e.g., Graves, Sarkis, & Zhu, 2013; Robertson & Barling, 2013; Robertson & Barling, 2017a). While this research provides initial insight into the role of leadership in predicting employees' pro-environmental behavior, a comprehensive understanding of the processes and mechanisms through which ETFL affects such behavior is lacking (Robertson & Barling, 2015b). Furthermore, research has not yet considered how leaders can help shape a work group climate that fosters environmental sustainability, and an understanding of the boundary conditions to the effects of ETFL on proenvironmental behavior has been neglected (Norton, Parker, et al., 2015; Robertson & Barling, 2015b). The goal of our research is to fill these knowledge gaps by examining how 738940J LOXXX10.