Context: Mindfulness-based interventions have shown promising therapeutic outcomes in improving well-being, mental health, general health, and quality of life, however, findings in this regard are inconsistent. The present study aimed at clarifying this inconsistency in the literature focusing on the Iranian studies through a systematic review and meta-analysis study. Evidence Acquisition: The databases of Pubmed, Scopus, Doaj, EBSCO, Iranmedex, MagIran, SID, and Comprehensive Human Sciences Portal, and additional resources were searched using the set terms of "mindfulness" OR "mindfulness-based cognitive therapy" OR "MBCT" OR "mindfulness-based stress reduction" OR "MBSR" AND "intervention" AND "well-being" OR "health" OR "quality of life" and the time limit of the records was set between March 2008 and May 2017. The language of search was restricted to English and Farsi. Only studies conducted on Iranian populations were selected in this study. Thirty-five studies conducted on 3013 subjects were assessed. Cochrane Q-test and I-squared index were used to detect the heterogeneity among results, and fixed effect model with a 95% Confidence Interval (CI) was applied. The effect size of mindfulness-based interventions on well-being, mental health, general health, and quality of life improvement, measured by Hedge's g ratios, were respectively 1.54, 1.08, 0.89, and 1.87. Results: The findings showed that the effect size of mindfulness-based interventions on well-being, mental health, general health, and quality of life improvement were of high magnitude, according to the Cohen's table. Conclusion: Mindfulness-based interventions effectively improved well-being, health, and quality of life.
