Companies are increasingly motivated to deal with the issue of sustainability not just from a moral standpoint, but also because these issues may be a major root of innovation. To achieve these sustainable innovations, the number of manufacturers who invest in specific resources has been increasing. Supplier contributions to manufacturing company sustainable innovations are influenced by particular investments and specially the human capital investments, which emphasizes the supplier's role in supporting the producer with sustainable innovations. The precise investments might help suppliers contribute to sustainable innovation. However, if a company invests too much in certain resources, such as human capital, the beneficial impacts of such investments may diminish, and the supplier's participation in sustainable innovation may be hampered. Various internal contingency variables can moderate the relationship between the specific investments and sustainable innovation contribution of suppliers. Thus, this study aims at this research gap. This research aimed to study the relationship between human capital specific investments and supplier sustainable innovation contribution in developed markets considering the role of learning and absorptive capacity, and market orientation. This research can be considered as the deductive, quantitative and field research in which the researchers collected the primary data by using a structured questionnaire. The validity and reliability of the questionnaire confirmed through different quantitative and qualitative approaches. The research sample was chosen by using the convenience sampling. In order to respond to the questionnaire surveys, top- and middle-level managers from 355 Swedish corporations in which suppliers have been incorporated in the corporation’s sustainable innovation activities addressed. Finally, A total of 960 questionnaires for 355 companies handed out, and 102 being returned and analysed. The regression curve estimation method revealed that there is a linear relationship between human capital specific investments and supplier sustainable innovation contribution. Besides, through the hierarchical multiple linear regression, the researchers demonstrated that absorptive capacity and market orientation can play the moderating role in this relationship, while the learning capacity can partially play such role in this relationship. Eventually, the theoretical, managerial and sustainability implications discussed and the limitations of the research in addition to the future research possibilities addressed.