Background: Tuberculosis (TB) remains a major public health challenge in Nigeria, with non-adherence to medication and clinic appointments significantly hindering disease control. Mobile health (mHealth) interventions, such as SMS and phone-calls, offer a promising approach to improve treatment adherence in resource-limited settings; however, evidence on their comparative and combined effectiveness remains limited in Nigeria. This study aimed to evaluate the impact of SMS and phone-call interventions on medication adherence and clinic appointment attendance among TB patients in Lagos State, Nigeria. Methods: A quasi-experimental study was conducted across 12 Directly Observed Treatment Short-course (DOTS) centres in four Local Government Areas of Lagos State, Nigeria. A total of 128 adults receiving TB treatment were allocated to four groups: SMS reminders every two days, bi-weekly phone-call reminders, a combined SMS and phone-call intervention, and standard care (control). Data were collected at baseline, 6th week, and 12th week follow-up. Clinic appointment attendance and medication adherence were analysed using age and education-level-adjusted generalized estimating equation (GEE) models with robust standard errors. Results: After adjusting for age and education, phone-calls and SMS significantly improved clinic appointment attendance compared to controls (phone-calls: OR = 2.97, 95% CI: 1.72–5.12; SMS: OR = 1.92, 95% CI: 1.05–3.50). Phone-calls were also most effective in improving medication adherence (OR = 18.09, 95% CI: 8.36–39.15), followed by SMS (OR = 7.72, 95% CI: 3.74–15.94). The combined intervention was not superior to the single-mode approaches. Time was a significant predictor of clinic attendance but not medication adherence. Estimated marginal means indicated that phone-call interventions consistently produced the highest predicted probabilities of adherence across outcomes. Conclusion: mHealth interventions, particularly phone-call reminders, are effective in enhancing clinic attendance and medication adherence among TB patients in Nigeria. Programmatic integration of phone-based follow-up into national TB control strategies is recommended to support long-term treatment adherence and improve patient outcomes. Read more