Background: In increasingly competitive academic environments, highly perfectionistic master’s students frequently report sleep problems. The mechanisms underlying this association, however, remain unclear. This study tested whether competitive personality mediates the perfectionism–sleep quality relationship and whether resilience moderates this mediated pathway. Methods: In a cross-sectional survey, 469 master’s students (Mage = 23.23 years, 53.5% male) completed validated measures of perfectionism, competitive personality, resilience, and sleep quality. Moderated mediation analyses (PROCESS Model 15) with 5000 bootstrap resamples were conducted. Results: Perfectionistic concerns and perfectionistic strivings both positively predicted competitive personality and were associated with poorer sleep quality. Resilience moderated the second stage of the mediation pathway. The indirect effects of both perfectionism dimensions via competitive personality on sleep quality were significant at low and moderate levels of resilience, but became non-significant at high resilience (index of moderated mediation = −0.001 for concerns, −0.003 for strivings; 95% CIs excluded zero). Conclusions: Competitive personality acts as a key mechanism linking perfectionism to poor sleep among master’s students. High resilience buffers this indirect pathway. Strengthening resilience while targeting perfectionistic cognitions may be a promising strategy for protecting sleep quality in competitive academic settings.