In the present study we sought to clarify links between religious exclusivity, as form of intergroup favoritism, and indices of psychosocial functioning. The study of in group favoritism has generally been invoked within Social Identity Theory and related perspectives. However, there is a lack of literature regarding religious exclusivity from the standpoint of social identity. In particular, the ways in which religious exclusivity is linked with other dimensions of religious belief and practice, and with psychosocial functioning, among individuals from different religious backgrounds are not well understood. A sample of 8545 emerging-adult students from 30 U.S. universities completed special measures. Measure of religious exclusivity was developed and validated for this group. The results suggest that exclusivity appears as predictor for impaired psychosocial functioning, low self-esteem and low psychosocial well-being for individuals from organized faiths, as well as for those identifying as agnostic, atheist, or spiritual/nonreligious. These findings are discussed in terms of Social Identity Theory and Terror Management Theory (TMT).