Self-efficacy is a key determinant of adherence to tuberculosis (TB) treatment, yet its psychosocial and spiritual dimensions remain underexplored in low-income industrial urban settings. This study examined the determinants of self-efficacy among TB patients in East Surabaya, Indonesia, focusing on the role of spirituality and age. A cross-sectional survey was conducted with 62 pulmonary TB patients selected by simple random sampling from community health centers in industrial districts. Data were collected using a validated questionnaire covering sociodemographic, spiritual, social, environmental, and health system factors. Structural equation modeling-partial least squares was employed to test hypothesized associations. The model demonstrated satisfactory validity and reliability. Results revealed that spirituality had the strongest positive influence on self-efficacy (β = 0.492, p < 0.001), while age was negatively associated (β = –0.245, p = 0.019). Social support, environmental conditions, and health system factors did not significantly affect self-efficacy. The final model explained 40.3% of the variance in self-efficacy (R² = 0.403). These findings highlight that spiritual beliefs and younger age are significant predictors of treatment confidence among TB patients in industrial urban environments. Incorporating spiritual care, faith-based counseling, and age-sensitive communication into TB programs may strengthen patients’ ability to complete therapy. Public health strategies in industrial areas should therefore integrate psychosocial and spiritual interventions alongside biomedical care to enhance adherence and treatment outcomes.