Surgical fear is a common psychological response among patients undergoing abdominal surgery and may adversely affect psychological well-being during the perioperative period. Individual psychosocial characteristics, particularly self-efficacy, may influence how patients perceive and cope with surgical fear. This cross-sectional observational study aims to determine the moderating effect of self-efficacy on the relationship between surgical fear and psychological well-being in patients undergoing abdominal surgery within the framework of Bandura's Social Cognitive Theory. Data will be collected preoperatively using validated questionnaires from 300 adult patients. The findings are expected to contribute to the identification of patients at risk for poor psychological outcomes and support the development of individualized nursing interventions.