| Number of studies (k): 46 | Effect size: Standardized Mean Difference | ABSTRACT: We conducted a pre-registered meta-analysis to appraise available evidence on two stress regulation strategies: Self-administered mindfulness meditation and heart rate variability biofeedback. We used a combination of keywords to find as many experimental and observational studies as possible, all of which highlighted a link between the two strategies and different components of stress (physiological, affective, and cognitive) and affective consequences of stress. To provide publication bias-corrected estimates, we employed multilevel regression-based methods and permutation-based selection models. We found no evidence for the efficacy of either strategy, which is mostly due to the low quality of the literature, high heterogeneity, high risk of bias, and the lack of Registered Reports. We recommend against relying on these interventions prior to obtaining a more reliable evidence base.