Out-group bias refers to the tendency to favor individuals within one's own group, known as the in-group, while holding negative views or stereotypes about those outside the group, referred to as the out-group. This bias can lead to discrimination and social division, as people may perceive out-group members as less trustworthy or competent. This phenomenon is often influenced by social identity theory, which suggests that individuals derive part of their self-esteem from their group memberships. Out-group bias can manifest in various contexts, including race, ethnicity, politics, and religion, affecting interpersonal relationships and societal dynamics.