ObjectiveTo investigate the roles of mobile health, or mHealth, in the psychosocial health of pregnant women and mothers.MethodsA systematic search was conducted in databases and grey literature including MEDLINE, Web of Science, CINAHL, PsycINFO, PsycARTICLES, Academic Search Complete, SocINDEX, Central Register of Controlled Trials, The Database of Abstracts of Reviews of Effects, NHS Economic Evaluation Database, Health Technology Assessment, UNICEF and WHO databases. Two searches were conducted to include original research articles published in English until 15 November 2021. Several tools were used to assess the risk of bias: revised Cochrane risk of bias tool for randomised trials, Risk of Bias in Non-randomized Studies of Interventions, National Heart, Lung, and Blood Institute quality assessment tool for cohort and cross-sectional studies, Critical Appraisal Skills Program checklist for qualitative studies and Mixed Methods Appraisal Tool for mixed-methods studies. Certainty of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation approach. Due to the high heterogeneity and variability of the included studies, data synthesis was conducted narratively.Results44 studies were included among 11 999 identified articles. Most studies reported mixed findings on the roles of mHealth interventions in the psychosocial health of pregnant women and mothers; mHealth improved self-management, acceptance of pregnancy/motherhood and social support, while mixed results were observed for anxiety and depressive symptoms, perceived stress, mental well-being, coping and self-efficacy. Furthermore, pregnant women and mothers from vulnerable populations benefited from the use of mHealth to improve their psychosocial health.ConclusionsThe findings suggest that mHealth has the potential to improve self-management, acceptance of pregnancy/motherhood and social support. mHealth can also be a useful tool to reach vulnerable pregnant women and mothers with barriers to health information and facilitate access to healthcare services. However, the high heterogeneity limited the certainty of evidence of these findings. Therefore, future studies should identify the context under which mHealth could be more effective.