Peer interaction is a substantial natural reward and influences the susceptibility to engage in drug use. Oxytocin (OT) regulates social behavior, thereby enhancing the reward value of social interaction. However, it remains unclear whether different-context peer interaction combined with OT exert different contributions to the rewarding effects of cocaine. Using female mandarin voles (Microtus mandarinus), a monogamous rodent with complex nonsexual social behavior, we first examined the conditioned place preference (CPP) and its persistence when subject voles were conditioned with cocaine (20 mg/kg) alone or conditioned with cocaine versus different peers (e.g. familiar female, unfamiliar female and unfamiliar male). Second, the CPP was examined when subjects received peripheral OT (1mg/kg) treatment and different context peer conditioning. We found that female voles maintained long-lasting cocaine preferences for over three weeks when conditioned with cocaine alone. The persistence time of cocaine CPP was shortened when simultaneously conditioned to a familiar female peer, while it was inhibited when simultaneously conditioned to an unfamiliar female or a male peer. The subject voles that received OT inhibited or reversed cocaine CPP when conditioned with familiar or unfamiliar males, respectively. These results indicate that different-context peer reinforcing differentially affects rewarding effects of cocaine. OT facilitates reward value of peer reinforcing, thereby contributing to attenuating cocaine preference and this effect varies with peer context.