Background <p>Attempts to resolve issues regarding parental leave for male employees must be made from the perspective of workplace fairness and the burden on supervisors. This study considered the relationship between negative feelings harbored by supervisors toward male employees when taking long-term parental leave and workplace stressors. The aim was to examine their interrelated effects, following a model that hypothesizes that workplace stressors lead to anger through situations that evoke a sense of unfairness regarding male parental leave.</p> Methods <p>An online survey was conducted targeting 400 workers, and a covariance structure analysis was performed.</p> Results <p>The proposed model showed good fit. “Stressors due to quantitative load” and “responsibility to employees” were associated with anger through perceptions of unfairness, particularly related to “lack of involvement in childcare” and “increase in one’s workload.” “Quantitative load” also had a direct effect on anger, while “responsibility to employees” was found to suppress it.</p> Conclusions <p>Workplace stressors can lead to supervisors’ anger toward male employees taking parental leave via perceived unfairness. While work–life balance measures may have unintended negative effects, this study contributes to organizational justice research by highlighting the role of workplace context in shaping reactions to male parental leave.</p>