In Korea's collectivistic culture, social comparison influences various domains, including mental health, emotion, personality, academics, and career. This meta-analysis reviewed 70 studies (135 effect sizes) on social comparison published in Korea up to August 29, 2025, with 26,669 participants ranging from adolescents to older adults, drawn from local to nationwide samples. Social comparison was primarily measured using the INCOM(Iowa-Netherlands Comparison Orientation Measure) and its modified versions. Among the 18 variables related to social comparison identified in this meta-analysis, strong associations were found with fear of negative evaluation (ESr = .60, 95% CI [0.55, 0.64]) and public self-consciousness (ESr = .59, 95% CI [0.54, 0.64]), followed by anxiety (ESr = .52, 95% CI [0.45, 0.58]), intolerance of uncertainty (ESr = .42, 95% CI [0.40, 0.45]), social anxiety (ESr = .40, 95% CI [0.35, 0.45]), and fear of missing out (ESr = .39, 95% CI [0.27, 0.50]). Medium effect sizes were revealed for career anxiety, depression, pursuit of happiness, socially prescribed perfectionism, and SNS addiction tendencies. Small effect sizes were observed for academic burnout, subjective well-being, self-esteem, and self-encouragement. In particular, subjective well-being, self-esteem, self-compassion, self-encouragement, and self-concept clarity were negatively related to social comparison, whereas other variables were positively related with statistical significance. This study systematically integrates research on social comparison in Korea and provides empirical evidence of its associations with diverse psychological and behavioral variables, offering important implications for future research.