Trust between superiors and subordinates within organizations serves as an important foundation not only for sharing authority and responsibility but also for cooperative problem-solving and task performance. This study examined what factors influence subordinates' trust in their superiors, focusing specifically on upward trust in superior-subordinate relationships. Based on prior research, subordinates' trust in superiors was defined in terms of calculus-based trust, knowledge-based trust, and identification-based trust. Hypotheses were derived and tested regarding the effects of supervisors' behavioral characteristics and competence, social similarity and the existence of personal ties (yongo) between superiors and subordinates, and the characteristics of the exchange relationship between them. This study employed a survey methodology, with a sample of 349 employees from 16 mid-sized domestic firms. The empirical results showed that supervisors' consideration, openness, and competence had significant positive effects on all types of trust. Meanwhile, social similarity between superiors and subordinates was expected to have significant effects on knowledge-based trust and identification-based trust, but this was only partially supported. Regarding the influence of personal ties, school ties (hakyeon) did not have a significant effect on trust, whereas regional ties (jiyeon) had effects on identification-based trust and knowledge-based trust, excluding calculus-based trust. This is interpreted as regional ties between superiors and subordinates enhancing emotional intimacy and mutual understanding, thereby contributing to trust formation, while suggesting that they do not yet significantly influence the formation of fair or transactional trust. In terms of exchange relationship characteristics, longer duration of the superior-subordinate relationship had a significant positive effect on knowledge-based trust and a negative effect on calculus-based trust. Meanwhile, expected future benefits had a significant positive effect on calculus-based trust. Future research should examine a broader range of factors that influence subordinates' trust in superiors. Furthermore, research on the effectiveness of trust is needed—specifically, investigating how trust affects various organizational effectiveness variables such as job satisfaction, organizational commitment, cooperation and coordination among members, and problem-solving and decision-making. Additionally, research is needed on how trust is formed in horizontal relationships among peers, as opposed to vertical superior-subordinate relationships. The accumulation of such research is expected to contribute to establishing a theory of organizational trust appropriate for the Korean context.