It is increasingly accepted that fairness constitutes an important motivational basis for the understanding of employee attitudes and behaviors in organizations, particularly of those contributions that go beyond prescribed roles. Based on social exchange theory, the present research proposes a multifoci model that accounts for the effects of justice on organizational citizenship behaviors. This model predicts that trust is an important mediator of the relationships among justice dimensions and organizational citizenship behaviors and attempts to extend current research in this area by considering not only the social exchange relationships of employees to the global organization, but also their relationships with immediate supervisors and coworkers. Results of a survey that addressed these constructs largely support our hypotheses and show that for the different foci considered (organization, supervisor and coworkers), trust is a mediator of the effects of justice dimensions on organizational citizenship behaviors targeted towards the corresponding foci.