Background: The effectiveness of mindfulness-based interventions (MBIs) on the mental health of perinatal women with or without current mental health issues remains unclear. Methods: Four electronic databases were searched from inception to October 1, 2021. Data synthesis, sensitivity analysis, subgroup analysis, and quality assessment were performed on the included studies. I2 and Q tests were applied to evaluate heterogeneity across studies. The risk of publication bias was assessed and visualized using a funnel plot. Results: A total of 21 RCTs with 1765 perinatal women were enrolled in the meta-analysis. We found MBIs were effective in reducing depression, anxiety, and stress, as well as increasing mindfulness in perinatal women with current mental health issues. However, MBIs were not prior to controls in reducing depression and stress, and increasing mindfulness in perinatal women without current mental health issues. The effectiveness of MBIs on reducing anxiety in perinatal women without current mental health issues was unclear. Limitations: Considerable heterogeneity was found in the pooled analyses of the RCTs in depression and anxiety in perinatal women with mental health issues and stress in perinatal women without mental health issues. Conclusion: MBIs could serve as a useful addition to existing support for perinatal women with current mental health issues. However, further studies were needed to explore and prove the effectiveness of MBIs on the mental health of perinatal women without current mental health.