Low medication adherence poses a great risk of poor treatment outcomes among patients with chronic diseases. Recently, mobile applications (apps) have been recognized as effective interventions, enabling patients to adhere to their prescriptions. This study aimed to establish the effectiveness of mobile app interventions for medication adherence, affecting features, and dropout rates by focusing on previous randomized controlled trials (RCTs). This study conducted a systematic review and meta-analysis of mobile app interventions targeting medication adherence in patients with chronic diseases. Electronic searches of eight databases were conducted on April 21, 2023, for studies published between 2013 and 2023. Comprehensive meta-analysis software was used to estimate the standardized mean difference (SMD) of pooled outcomes, odds ratios (ORs), and confidence intervals (CIs). Subgroup analysis was applied to investigate and compare the effectiveness of the interventional strategies and their features. The risk of bias of the included RCTs was evaluated by applying the risk of bias tool. Publication bias was examined using the fail-safe N method. Twenty-six studies with 5,174 participants were included (experimental group 2603, control group 2571). The meta-analysis findings showed a positive impact of mobile apps on improving medication adherence (OR = 2.371, SMD = 0.279). The subgroup analysis results revealed greater effectiveness of interventions using interactive strategies (OR = 2.652, SMD = 0.283), advanced reminders (OR = 1.849, SMD = 0.455), data-sharing (OR = 2.404, SMD = 0.346), and pill dispensers (OR = 2.453). The current study found that mobile interventions had significant effects on improving medication adherence. Subgroup analysis showed that the roles of stakeholders in health providers' interactions with patients and developers' understanding of patients and disease characteristics are critical. Future studies should incorporate advanced technology reflecting acceptability and the needs of the target population.