IntroductionMaintaining physical and mental health is essential for healthy ageing. It can be supported by modifying lifestyle factors such as physical activity and diet. Poor mental health, in turn, contributes to the opposing effect. The promotion of healthy ageing may therefore benefit from holistic interventions integrating physical activity, diet and mental health. These interventions can be scaled up to the population level by using mobile technologies. However, systematic evidence regarding the characteristics and effectiveness of such holistic mHealth interventions remains limited. This paper presents a protocol for a systematic review that aims to provide an overview of the current state of the evidence for holistic mHealth interventions, including their characteristics and effects on behavioural and health outcomes in general adult populations .Methods and analysisWe will conduct a comprehensive search for randomised controlled trials and non-randomised studies of interventions published between January 2011 and April 2022 in MEDLINE, Embase, Cochrane Central Register of Controlled Trials, PsycINFO, Scopus, China National Knowledge Infrastructure and Google Scholar (first 200 records). Eligible studies will be mHealth interventions targeting general adult populations with content on physical activity, diet and mental health. We will extract information on all relevant behavioural and health outcomes, as well as those related to intervention feasibility. Screening and data extraction processes will be carried out independently by two reviewers. Cochrane risk-of-bias tools will be used to assess risk of bias. We will provide a narrative overview of the findings from eligible studies. With sufficient data, a meta-analysis will be conducted.Ethics and disseminationEthical approval is not required because this study is a systematic review based on published data. We intend to publish our findings in a peer-reviewed journal and present the study at international conferences.PROSPERO registration numberCRD42022315166.