6. ConclusionsBuilding on the NRBV, eco-innovation, and supplier involvement literature, our results suggest that supplier eco-innovationcapabilities and alliance partner diversity can influence the development of inter-organizational eco-innovations. We contribute tothe eco-innovation literature by undertaking one of the firstempirical studies of the determinants of inter-organizational ecoinnovation when suppliers are involved in NPD. Using the researchcontext of the Toyota supplier association, our empirical analysisreveals that supplier electric capabilities and hybrid capabilities areassociated with a significant increase in the degree of ecoinnovation co-patenting. However, we find mixed results for theextent to which alliance partner diversity moderates the relationship between supplier eco-innovation capabilities and copatenting. Finally, we have also identified some of the similaritiesand differences between Japanese automakers in how they developinter-organizational eco-innovations within their suppliernetworks.AcknowledgementsWe would like to thank our universities for providing thefunding and resources for this research project that explores recentchanges in the management practices, supply chain and innovationactivities of firms in the Japanese automotive industry. Funding wasprovided for access to the research databases used in this paper.Declarations of interest: none.