Transgender and gender diverse (TGD) individuals face significant healthcare barriers, resulting in inequities and unmet needs. Mobile health (mHealth) applications offer promising solutions by providing accessible, cost-effective, personalized, and gender-affirming care. This systematic review, conducted using PRISMA 2020 guidelines and the PICO framework, screened 5005 records from 4 databases and included 11 articles. The review aimed to identify key features of mHealth apps developed for TGD individuals, focusing on theoretical frameworks, design strategies, and their approaches to addressing healthcare barriers. Key challenges in developing mHealth apps include implementing systemic changes in healthcare settings to combat stigma and discrimination, grounding app development in TGD-specific theoretical frameworks, adequately addressing stressors and protective factors, and overcoming methodological limitations that hinder the evaluation of health outcomes. Overcoming these challenges requires rigorous research methodologies, inclusive designs, reliance on evidence-based TGD frameworks, and stronger collaboration among researchers, healthcare providers, and TGD communities.