IntroductionNutrition education is the cornerstone to maintain optimal pregnancy outcomes including gestational weight gain (GWG). Nevertheless, default for appointments is common and often lead to suboptimal achievement of GWG, accompanied with unfavourable maternal and child health outcomes. While mobile health (mHealth) usage is increasing and helps minimising barriers to clinic appointments among pregnant mothers, its effectiveness on health outcomes has been inconclusive. Therefore, this study aimed to address the gap between current knowledge and clinical care, by exploring the effectiveness of mHealth on GWG as the primary outcome, hoping to serve as a fundamental work to achieve optimal health outcomes with the improvement of secondary outcomes such as physical activity, psychosocial well-being, dietary intake, quality of life and sleep quality among pregnant mothers.Methods and analysisA total of 294 eligible participants will be recruited and allocated into 3 groups comprising of mHealth intervention alone, mHealth intervention integrated with personal medical nutrition therapy and a control group. Pretested structured questionnaires are used to obtain the respondents’ personal information, anthropometry data, prenatal knowledge, physical activity, psychosocial well-being, dietary intake, quality of life, sleep quality and GWG. There will be at least three time points of data collection, with all participants recruited during their first or second trimester will be followed up prospectively (after 3 months or/and after 6 months) until delivery. Generalised linear mixed models will be used to compare the mean changes of outcome measures over the entire study period between the three groups.Ethics and disseminationEthical approvals were obtained from the ethics committee of human subjects research of Universiti Putra Malaysia (JKEUPM-2022-072) and medical research & ethics committee, Ministry of Health Malaysia: NMRR ID-22-00622-EPU(IIR). The results will be disseminated through journals and conferences targeting stakeholders involved in nutrition research.Trial registration numberClinicaltrial.gov ID:NCT05377151.