mHealth interventions play an increasingly important role in health behavior change for gestational diabetes or peripartum obesity management. This qualitative systematic review and meta-synthesis aims to explore women's perceptions of mHealth behavior change interventions for gestational diabetes and/or overweight/obesity management during pregnancy and the postpartum period. Cumulative Index of Nursing and Allied Health Literature (CINAHL), Cochrane, Excerpta Medica Database (EMBASE), Medical Literature Analysis and Retrieval System Online (MEDLINE), and Psychological Information Database (PsycINFO) databases were searched using a Sample, Phenomenon of Interest, Design, Evaluation and Research type (SPIDER) concept framework through to February 2024. Included studies were quality assessed using the Critical Appraisal Skills Programme checklist. Study findings were evaluated using reflexive thematic analysis and GRADE-Confidence in the Evidence from Reviews of Qualitative Research (CERQual) checklist. We identified 29 studies, representing 604 women's views from one upper middle-income and nine high-income countries. Two themes were generated: mHealth as a supportive tool; and mHealth as a personalizable tool. Women highlighted the importance of self-monitoring, information trustworthiness, peer support, motivational tools (goal setting, risk awareness, and problem solving) and convenience in achieving behavior change using mHealth technology. They suggest mHealth programs incorporate these elements to support user engagement and improved health outcomes. Understanding what women want as mHealth users is particularly important for effective interventions in gestational diabetes, weight management, and chronic disease prevention. Creating a better, more woman-centered experience by addressing central engagement issues should result in improved maternal health outcomes.