Rheumatic diseases are a group of inflammatory conditions that significantly impact physical and mental health. Ecological momentary interventions have shown promising effects among individuals with rheumatic diseases as they can deliver the most appropriate type and intensity of intervention tailored to their needs in real time, but their effectiveness has not been systematically reviewed and examined. To examine the effectiveness of ecological momentary interventions in reducing pain, improving mental health, and enhancing quality of life in individuals with rheumatic diseases. Systematic review and meta-analysis. A literature search was conducted in nine electronic databases from inception to April 2024. Randomized controlled trials (RCTs) examining the impact of ecological momentary interventions on pain, mental health, and/or quality of life in rheumatic disease populations were included. Two authors independently screened studies, extracted data, and assessed the risk of bias using Cochrane's bias risk tool for randomized trials (ROB 2). The intervention effect was estimated by calculating the standardized mean difference (SMD) and 95% confidence interval (CI) with R 4.3.3 software. The certainty of the evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. Sixteen RCTs with 1869 participants were included. Ecological momentary interventions significantly reduced pain (SMD = 0.18, 95% CI: 0.04-0.33) and marginally improved quality of life (SMD = 0.29, 95% CI: -0.01-0.60) versus controls. Subgroup analyses revealed greater effects for ecological momentary interventions with daily reminders on pain reduction (SMD = 0.21, 95% CI: 0.06-0.36) and quality-of-life improvement (SMD = 0.45, 95% CI: 0.02-0.88), as well as for ecological momentary interventions involving human contact on pain (SMD = 0.31, 95% CI: 0.10-0.52) and quality of life (SMD = 0.60, 95% CI: 0.25-0.95). However, both the primary analysis and subgroup analyses showed that ecological momentary interventions did not significantly improve anxiety and depression. Ecological momentary interventions could alleviate pain and enhance quality of life in rheumatic disease populations, but had no significant effect on improving mental health. Future research should explore optimizing ecological momentary intervention design and implementation and further examine its effects on mental health outcomes in this population.