The purpose of this study is to analyze the relations between social competence and mental well-being through perceptions of giftedness in gifted and general students. Data are collected from 359 gifted and general South Korean students (M[subscript age] = 13.54) and analyzed by structural equation modeling. The results reveal that, first, gifted students perceive higher giftedness, social competence, and mental well-being than general students. Second, the perceived giftedness level of general students has a statistically significant partial positive mediated effect on mental well-being related to social competence. The interactive effect of social competence and perceived academic achievement on mental well-being decreases as gifted students perceive higher academic achievement. This research will facilitate the precise understanding and nurturing of gifted students under the national law and assist in constructing giftedness.