The importance of environmental sustainability initiatives (ESI) for engineering and supply chain management practice and research is undeniable. However, despite the widespread attention to this domain, investigations in the effects of ESI on performance have been ambiguous and led to contradicting results, calling for the examination of contingencies influencing the relationship. This study works to bring insight and clarity into this debate by a comparative analysis of ESI among efficient and inefficient plants in Europe and the U.S. Specifically, using a sample of 402 plants located in Europe and the U.S., we study the impact of an explicit set of ESI (recycling, waste reduction, pollution prevention, ISO 14000 certification) on plant efficiency, an important performance measure which is, however, rarely considered. Basing our rationale on the resource-based view of the firm, we suggest that plants more heavily engaged in ESI are also characterized by a greater level of efficiency. We test this contention in both European and U.S. plants. Extending this cross-national comparison, we further study whether the emphasis on ESI differs in the two country groups. Relying on institutional theory, we suggest that the pursuit of ESI is enhanced among European plants, compared to their U.S. counterparts. Our findings and conclusions draw attention to the importance of contingencies to be considered and bring light to the seemingly contradictory findings in prior research. Important implications for engineering and supply chain management practice and research are highlighted.