Abstract: Background: The fast spread of mobile health (mHealth) technologies in low- and middle-income countries (LMICs) has been praised for its potential to transform healthcare delivery, particularly among underserved groups. However, the efficacy of these tools is frequently moderated by complex socio-demographic factors that influence adoption, engagement, and health outcomes. Aim: This narrative review critically investigates how age, gender, education, poverty, and geographic location influence the adoption and effectiveness of mHealth interventions in Sub-Saharan Africa (SSA), with an emphasis on equitable access and program sustainability. Methodology: A systematic narrative methodology influenced by Braun and Clarke's thematic analysis framework and CRD recommendations was used to synthesise peer-reviewed literature and grey sources. The study uses theoretical frameworks such as the Health Belief Model, the COM-B framework and Fisher & Fisher's IMB model to understand behavioural and systemic trends. Findings: According to the findings, mHealth uptake is stratified by age and gender, with younger, urban, educated users benefiting the most. Key impediments include digital illiteracy, network restrictions, sociocultural norms, and economic inequalities, while facilitators include user-centred design, community-based interventions, and telecom collaborations. Conclusion: The review finds that a one-size-fits-all mHealth design is insufficient and it advocates for intersectional, equity-informed solutions that take into account different user experiences, strong policy frameworks, long-term funding, and ethical data governance.