We examined whether police officer self-legitimacy moderates the effect of supervisor procedural injustice on organizational trust. Data from a sample of sheriff’s deputies (N = 510) were used to test this question. Results from multivariate models showed that (a) supervisor procedural injustice was associated with less organizational trust among deputies, (b) self-legitimacy was positively associated with trust in the agency, and (c) self-legitimacy conditioned the effect of procedural injustice on organizational trust. These findings advance the literature in several ways. First, this study provides one of the first empirical examinations of organizational trust—a concept widely studied in the business-related literature—in a police agency context. The findings suggested that supervisor procedural injustice and officer self-legitimacy are key correlates of trust in a police agency. Second, the results further underscore the importance of self-legitimacy by revealing that it can serve as a protective factor against negative experiences within the organization.