We aimed to explore how romantic relationship status affects the moderating effect of peer relationships on associations between parent-youth relationships and Self-differentiation. Chinese college students (N=389) completed measures to assess the Self-differentiation, parent-youth relationships, peer relationships, and romantic relationships. Results revealed that the interaction effect between peer discord and father-youth discord was not significant for romantically involved participants (?=0.22, SE=0.02, p=0.13), while the interaction effect between peer discord and father-youth discord was significant for single participants (?=0.20, SE=0.01, p<0.05). In other words, the protective effect of peer relationships on the associations between parent-youth relationships and differentiation of self was effective only for single participants. The theoretical and practical implications of these findings are discussed.