Due to strategic motivations and pressures from various stakeholders, firms are adopting green supply chain management (GSCM) practices to extend environmental sustainability objectives to suppliers. Although it seems that an increasing number of firms is seeing environmental sustainability as a source of competitive advantage, there is a large gap of research focusing explicitly on the connection between competitive strategy and GSCM. It is also necessary to examine GSCM practices in several operational contexts. This article refines the competitive strategy approach and examines external GSCM strategies along the tiers of supply chain from the perspective of logistics users and providers using a dataset of 128 manufacturing, 110 trading and 144 logistics firms operating in Finland. The results reveal a connection between competitive strategy and GSCM strategy. Marketing differentiators and firms pursuing hybrid strategies tend to use more advanced GSCM strategies to manage the environmental performance of their suppliers. For them, GSCM seems to be a way to differentiate products and services, and to minimise the risk of potential losses resulting from poor environmental performance by suppliers. The results highlight the need to understand the role of competitive strategy in GSCM adoption, both in academia and in business.