Signaling norms are social norms, the adherence to which by agent A changes or reinforces agent B’s beliefs about agent A’s belonging and commitment to a social group. Signaling norms is a concept that constitutes a novel step in the development of both the theory of social norms and signaling theory. While cooperation or coordination norms emerge due to a demand for reducing externalities of individual behavior (e.g., smoking, congested escalators), signaling norms emerge due to a demand for reducing uncertainties regarding individuals’ belonging and commitment to social groups. The concept thus offers a new way to formalize processes of boundary making in intergroup relations and provides alternative explanations for occurrences such as table manners, dress codes, religious badges, jargon, and sense of humor. After introducing the concept of signaling norms, I will present results from an agent-based computational model showing how and when intergroup conflict can promote the emergence of signaling norms.