There is increasing evidence of a strong comorbidity between autism and epilepsy. One pathway that may be a significant mediator of the two conditions is the mammalian target of rapamycin (mTOR) pathway. The mTOR pathway is a key component of mRNA translation, cell growth control, and cell proliferation. Hyperactivation of the mTOR pathway has been reported in several animal models of epilepsy and in some mouse models of autism. One of the core diagnostic criteria for autism is aberrant social behavior. The focus of this project was to observe the effect of deletion of the PTEN gene on social behavior in mice. PTEN serves as a regulatory inhibitor of the mTOR pathway, so its deletion results in hyperactive mTOR pathway. The social partition and social chamber tests were used to measure social behavior in PTEN knockout and wildtype. The outcome of both tests illustrated that the PTEN knockout mice had a significant decrease in social behavior. These results indicate that an overactive mTOR pathway may indeed result in an autistic phenotype, and comorbidity between epilepsy and autism should further be considered.