Parental psychosocial health can have a significant effect on the later psychological health of the child. Parenting programs have been shown to have an effect on the emotional and behavioral adjustment of children, and this review examined such programs' effect on parental psychosocial well-being. We searched a range of electronic databases and included randomized controlled trials that compared a group-based parenting program with a control condition and used at least 1 standardized measure of parental psychosocial health. We used a random effects meta-analysis, and we report standardized mean differences (SMD) and 95% confidence intervals (CI) for all outcomes. We included 48 studies with 4,937 participants and evaluated 3 types of programs: behavioral, cognitive-behavioral, and multimodal. Overall, we find parents' participation in group-based parenting programs is associated with statistically significant short-term improvements in depression (SMD -0.17, 95% CI -0.28 to -0.07), anxiety (SMD -0.22, 95% CI -0.43 to -0.01), stress (SMD - 0.29, 95% CI -0.42 to -0.15), anger (SMD -0.60, 95% CI -1.00 to -0.20), guilt (SMD -0.79, 95% CI -1.18 to -0.41), confidence (SMD -0.34, 95% CI -0.51 to -0.17) and satisfaction with the partner relationship (SMD -0.28, 95% CI -0.47 to -0.09). However, only stress and confidence continued to be significant at the 6-month follow-up, and none were significant at 1 year. The findings of this review support the use of parenting programs to improve the short-term psychosocial wellbeing of parents. Further training might be required to ensure that these benefits are maintained.