The purpose of this study was to investigate research findings related to family functioning and the factors associated with it. The researchers were guided by the following research questions: What are the factors and associated effect sizes frequently investigated in previous studies of family functioning? Methods: The researchers selected 96 studies conducted in Korea between 1989 and 2011 and calculated 850 effect sizes. They identified six main factors (parent and child demographic variables, parent psychosocial variables, child psychological variables, family system variables, and family health-related variables) and 31 sub-factors. They calculated the effect sizes from the selected studies using meta-analytic method, and they analyzed the results. Results: Regarding overall family functioning, results indicated a large effect size for family communication and medium effect sizes for family support, existence of disability or illness, satisfaction with life, and family structure. In addition to parents’ age, education, depression, leisure, parenting style, and stress level, children’s self-esteem appeared to be a significant factor with regard to family functioning. Conclusions: The researchers discussed the findings and offered suggestions.