AbstractThis study sought to test actor and partner effects of rejection sensitivity on romantic relationship outcomes. In total, 200 participants (100 mixed-sex couples; mean age = 36.17 ± 11.11 years) completed questionnaire measures at a single timepoint. After controlling for participant age and relationship duration, results showed that personal rejection sensitivity, but not partner rejection sensitivity, predicted self-report relationship outcomes for both men and women. Higher levels of rejection sensitivity were associated with lower levels of relationship satisfaction and relationship commitment, and higher levels of jealousy and self-silencing behaviour. Rejection sensitivity was unrelated to relationship investment. Multiple mediation models further demonstrated that anxious and avoidant attachment styles mediated associations between rejection sensitivity and relationship outcomes. Analyses of couple similarity in rejection sensitivity showed that couples report worse relationship outcomes when both partners score high on rejection sensitivity. Overall, the study provides evidence that rejection sensitivity has an important role in relationship outcomes among couples. Creating awareness of the role of rejection sensitivity in relationship outcomes might be a useful approach to improving relationship quality.