People from different cultural backgrounds vary in how they define, perceive, and react to violations of relational boundaries. Muslim cultures are diverse and include nearly one in four people in the world, yet research on their relational and moral norms is scarce. We contribute to narrowing this gap by studying gheirat, a moral-emotional experience ubiquitous in Muslim Middle Eastern cultures. In four mixed-methods studies, we study how gheirat is experienced, what situations elicit it, and its social functions among Iranian adults (N = 1,107) using qualitative interviews, scenario- and prototype-based surveys, and an experiment. The prototypical experience of gheirat consisted of diverse appraisals (including sense of responsibility, insecurity, and low self-worth) and emotional components (including hostility, social fears, and low empowerment). We identified three types of relational violations that elicit gheirat: harm or insult to namoos (people and self-relevant entities one is obliged to protect), romantic betrayal by namoos, and intrusions by a third person. Each violation type led to a distinct variant of the prototype. Contrary to folk theories of gheirat, we did not find support for the idea that gheirat is a predominantly male experience. However, an experiment on the signaling effects of gheirat revealed that gheirat expressors are ascribed both positive and negative traits, but positive traits prevail for men and negative traits prevail for women. We discuss how the results contribute to a better understanding of Iranian social life and intercultural contact, as well as the implications for theories of emotion and the cultural logic of honor.