Past research indicates that individuals who were formerly religious (religious dones) and individuals who were never religious (religious nones) differ on important psychological and behavioral characteristics. Other research demonstrates that religious and nonreligious individuals experience social identity threat; however, this research has only been conducted in the United States. Thus, we examined social identity threat among currently religious, formerly religious, and never religious individuals across three cultural contexts: religious Western (United States), secular Western (the Netherlands), and Eastern (Hong Kong). Two studies (N = 4,697) drawn from three countries (Hong Kong, the Netherlands, and United States) examined the degree to which formerly religious individuals (i.e., religious dones) conceal their identity, relative to currently religious and never religious individuals. In Study 1 (N = 3,071), we found that religious dones report less public–private identity overlap—that is, greater identity concealment—in a religious culture (i.e., United States). In Study 2 (N = 1,626), we replicated these results and extended the findings to belongingness. In addition, belongingness mediated the association between religious identity and identity concealment among U.S. participants. These results suggest social costs of religious deidentification in religious settings: religious dones feel less belonging and consequently conceal their identity.