The phenomenon of global warming and climate change has increasingly attracted attention by researchers in the field of supply chain and operations management. Firms have developed efficient plans and intervention measures to reduce greenhouse gas (GHG) emissions. While a majority of research in supply chain management has adopted a firm-centric view to study environmental management, this dissertation focuses on the context of GHG emissions reduction by considering a firm’s vertical and horizontal relationships with other parties, and the associated spillover effects. A theoretical framework is first proposed to facilitate the field's understanding of the possible spillover effects in GHG emissions reduction via vertical and horizontal interactions. Two empirical studies are then presented to test the spillover effect in GHG emissions reduction, focusing on the vertical interactions - when firms interact with their supply chain members. Drawing data from Bloomberg Environmental Social and Governance, and Bloomberg SPLC, this study conducts econometric analyses using various models. The results suggest that first, a higher level of supply chain GHG emissions is associated with the adoption of emissions reduction programs by a firm, and that this supply chain leakage contributes to the firm’s financial performance. Second, a firm's supply base innovativeness can contribute to its internal GHG emissions reduction, and this effect is contingent on a firm's supply base structure. As such, this dissertation answers the recent call in the field of supply chain and operations management for more empirical research in socially and environmentally responsible value chains. Further, this study contributes to the literature by providing a better understanding of the externalities that value chain members can impose on one another when pursuing sustainability goals.