Background and Objectives: Metabolically unhealthy obesity is characterized by the presence of cardiovascular metabolic risks such as hypertension, dyslipidemia, and hyperglycemia. Research has shown a correlation between remnant cholesterol (RC) concentrations and abdominal obesity in children. However, the effect of RC concentration on metabolically unhealthy obesity remains unclear. Methods and Study Design: This study included 3114 Chinese adolescents who received health check-ups. We used logistic regression models and receiver operating characteristic analysis to evaluate the correlation between RC concentration and metabolically unhealthy obesity in a cross-sectional design. Results: After controlling for possible confounding variables, we found that individuals in the top and fourth quintiles of RC concentrations had a significantly higher likelihood of developing metabolically unhealthy obesity compared to those in the bottom quintile (ORs, 4.810 and 1.836; 95% CIs, 3.209–7.212 and 1.167–2.890, respectively). The risk of metabolically unhealthy obesity tended to increase with RC concentration (ptrend<0.001). In addition, boys showed positive associations between RC concentration and both BMI (r = 0.305, p<0.001) and waist circumference (r = 0.306, p<0.001). According to the analysis, the predictive accuracy of metabolically unhealthy obesity was 0.736 (95% CI, 0.690–0.781) for boys and 0.630 (95% CI, 0.573–0.687) for girls. The ideal prediction threshold was 0.66 for boys and 0.59 for girls. Conclusions: Our findings indicate that elevated RC concentration is linked to a higher likelihood of developing metabolically unhealthy obesity in young individuals, regardless of other known risk factors.