Objective: Tuberculosis (TB) is a public health problem in many countries, including Indonesia. To enhance the treatment of TB patients, improving patients' perceptions of the disease and treatment is essential. This study aims to assess the effects of a peer support group program on the Perceived Severity, Perceived Benefits, Perceived Barriers, and Self-Efficacy of TB patients undergoing treatment. Methods: Employing a quasi-experimental one-group pre-test-post-test design, the study was conducted at the Cimanggis Community Health Centre in Depok City. A total of 32 TB patients were selected via a total sampling technique. Over two months, the intervention included seven sessions encompassing participant selection, psychoeducation, cognitive restructuring, breathing exercises, activity scheduling, problem-solving, and health behavior maintenance. Instruments utilized included validated Health Belief Model and Sociodemographic Profile Questionnaires. Data analysis was performed using paired sample t-tests. Results: This study showed a significant difference between pre-test and post-test scores in each domain of Perceived Severity (p=0.000), Perceived Benefits (p=0.000), Perceived Barriers (p=0.000), and Self-Efficacy (p=0.000). The average score of each part increased significantly. Conclusions: The peer support group program effectively enhanced TB patients' perceptions and confidence in their treatment approach. The pivotal roles of community nurses in facilitating peer support groups, delivering TB education, and overseeing program participation underscore the value of community-based interventions in TB management. © (2025), American Psychological Association