Competition is widely promoted as a mechanism for enhancing employee motivation and organizational performance. However, its unintended costs for female managers remain underexplored. This study examines how performance-oriented competition (POC) affects affective organizational commitment (AOC) through workplace interpersonal strain (WIS) and work overload strain (WOS), and whether job autonomy moderates these relationships among female managerial employees. Data were drawn from the seventh wave of the Korean Women Manager Panel, a large-scale national survey in South Korea. The final sample comprised 1325 females across 413 organizations. Mediation and moderation analyses were conducted using the PROCESS macro with bootstrapped confidence intervals. Results indicate that POC is positively associated with both WIS and WOS, which are in turn negatively associated with AOC. Both forms of strain significantly mediate the relationship between competition and commitment, with the WIS pathway being stronger. Job autonomy does not affect the relationship between POC and WIS but unexpectedly strengthens the positive association between POC and WOS. These findings suggest that competitive work systems may impose hidden costs by weakening female managers’ organizational commitment. This study extends research on competitive climates and challenges the assumption that job autonomy is uniformly beneficial. Organizations should exercise caution when relying on competition and autonomy as motivational tools.