Teachers report high levels of occupational stress, which is associated with teacher turnover and potential negative consequences for students. Mindfulness-based interventions (MBIs) may improve the protective factors that buffer educators against occupational stress. Although previous meta-analytic reviews synthesized the effects of MBIs for healthy and clinical samples of adults, this study was the first to synthesize the effects of MBIs for teachers (grades pre-K through 12). A total of 347 effect sizes from 29 studies (N = 1,493) were synthesized using metaregression with robust variance estimation. Overall, MBIs had a medium treatment effect on teacher outcomes (g = .601, SE = .089). Visual and statistical evidence of publication bias suggested this estimate may be positively biased. Three potential study-level moderators for overall effects were also examined, but none were statistically significant. MBIs were associated with small-to-medium positive effects on therapeutic processes and therapeutic outcomes. MBIs had the smallest effects on measures of classroom climate and instructional practices. Overall, findings were similar to other meta-analytic reviews of MBIs for nonclinical adult populations and working professionals. The literature on MBIs for teachers appears to have similar gaps as research on MBIs for adults (e.g., Davidson & Kaszniak, 2015), including the primary use of self-report measures, the lack of active treatment comparisons, and rare reporting of treatment fidelity data. Directions for future research and implications are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).