The findings described in this study support the importance of asset-specifc investments in the relationship between a customer’s environmental performance requirements and their potential to improve the supplier’s commitment to its environmental responsibilities. Without Investment the supplier appears much less likely to be responsive to the customer’s requirements for environment-related performance improvements. These findings are supported by observations made during earlier discussions with operations managers in Australian automotive component supplier firms such that suppliers were desirous of emulating or adopting their customer’s environmental practices especially where the supply relationship was described by the supplier as being most critical to their firm’s survival.