As the innovation process, specifically open innovation, does not occur in isolation, the interactions and interface between relevant stakeholders is an interesting object of study. As it seeks collaboration and access to valuable resources, an organization has to establish relationships with its stakeholders, something that has barely been explored from the open innovation perspective. By focusing on this, the present study aims to analyze the connection between different stakeholders’ relationships and open innovation. Based on the microfoundations of Stakeholder Theory and the open innovation literature, we propose three hypotheses. Considering our objective, we examine 710 observations of Brazilian companies from between 2008 and 2017 and use a longitudinal multinomial logistic model to test the hypotheses proposed. Our results show the relevant role of positive reciprocity and justice in stakeholders’ relationships in the development of open innovation. Therefore, our results suggest that by delivering more positive reciprocity and justice to stakeholders in their relationships, the organization receives mutually contingent bonuses that increase the probability of developing open innovation.