From completing the census to filling out an employee engagement survey, people are often asked to provide demographic information about themselves, such as their gender, by selecting their identity from a list of options. However, the options provided in such situations are seldom unlimited—they typically reflect only a subset of possible identities. In the present research, we explored social identity threat caused by subtle acts of omission, specifically, situations in which social identity information is requested but one’s identity is not among the options provided. We predicted that being unable to identify with one’s group—e.g., in the demographics section of a job application form—may signal social identity devaluation, eliciting negative affect (e.g., anger), reducing anticipated organizational belonging, and increasing the importance of the omitted identity to group members’ sense of self. Six pre-registered experiments (N = 2,964 adults) sampling members of two minority identity groups (i.e., gender minorities and members of a minority political party) support these predictions. Our findings document the existence of a subtle but likely pervasive form of social identity threat. We discuss implications for organizations concerned with reducing social identity threat for employees.