Research examining the effects of group-based mindfulness interventions on executive functioning have yielded inconsistent findings, with some reports of enhanced performance and other reports of null findings. Inconsistencies in the literature may be due to methodological differences across studies, including the type of control group employed and sample characteristics (e.g., clinical vs. non-clinical samples). The current systematic review and meta-analysis examined the effect of group-based mindfulness programs on executive functioning in persons 18+ years of age. Following the standards for systematic review, a total of 29 studies were included in the meta-analysis, of which 21 comparisons contributed to the analysis of inhibition; nine to working memory; nine to attention shifting; and four to the analysis of verbal fluency. After removing outliers, random effects models suggested a small but significant synthesized effect of group-mindfulness training on overall executive functioning (95% CI = 0.256, 0.725). Examination of executive subdomains after removing outliers suggested a small, statistically significant effect for inhibition (95% CI = 0.055, 0.387), working memory (95% CI = 0.010, 0.437), and verbal fluency (95% CI = 0.071, 1.931). No significant pooled effects were found for attention shifting. A priori subgroup analysis by randomization, type of control group, and sample cohort revealed inconsistent results. Overall, the current review suggests that the effect of group-based mindfulness training on executive functioning is not robust.