Rapamycin which is an inhibitor of mammalian target of rapamycin (mTOR), has effects as antineoplastic, retarding aging, anti-inflammatory and neuroprotective. Aim of this study is to investigate the effects of rapamycin on maternal aggression in rats. In this study 63 Wistar female rats were used. The animals were divided into 3 groups: the solvent (DMSO) group, the 5 mg/kg rapamycin group, and the 10 mg/ kg rapamycin group. For behavioral testing the resident-intruder paradigm was used. The groups were compared in terms of the latency to the first aggressive behavior, the number of attacks, the total duration of aggressive behaviors and the intensity of attacks. When the groups were compared in terms of the latency to the first aggressive behavior, it was found that 5 and 10 mg/kg rapamycin groups were significantly prolonged latencies compared to the control group. When were evaluated the number of aggressive behaviors, total duration of aggressive behaviors and average severity of attacks it was found that 5 mg/kg rapamycin group's values were significantly lower than the control groups. These results show that acute administration of rapamycin, especially in 5 mg/kg dose of rapamycin prolongs the latency of maternal aggression, and decreased the number of attacks, the intensity of attacks and the total duration of aggressive behaviors in rats. Therefore rapamycin may have potential for use as a sedative drug, however it is necessary to conduct further studies.