How does single party dominance influence interpersonal trust? We draw on evidence from trust games played by more than 2,000 subjects in South Africa, where, since Apartheid, race-based social enmity has persisted under democratic competition characterized by single-party dominance. We find partisan-based trust discrimination is most pronounced for those who identify with the main opposition party and is driven by strong distrust of rival partisans. These findings underscore how electoral competition, in general, shapes trust across party lines and suggest one-sided competition, in particular, has asymmetrical spillover effects. Moreover, this study provide additional evidence regarding the relative weights of trustworthiness stereotypes tied to partisanship and race.