<b><i>Introduction:</i></b> Obesity in childhood and adolescence is associated with complications that resemble those seen in hypercortisolism. Hair cortisol concentration (HCC) in children is a reliable marker of long-term endogenous cortisol concentrations. We determined HCC in overweight and obese children and adolescents, and examined the relation between HCC and other cardiometabolic parameters. <b><i>Methods:</i></b> Three hundred children and adolescents aged 4–18 years (mean age ± standard error of the mean [SEM]: 10.49 ± 0.15 years; 140 [46.7%] obese, 94 [31.3%] overweight, 66 [22%] of normal BMI; 76 males, 224 females) were studied prospectively. Blood samples for determination of hematological, biochemical, and endocrinologic parameters were obtained. Systolic (SBP) and diastolic blood pressure (DBP) was determined. Scalp hair samples were collected from the posterior vertex, and HCC was measured using an electrochemiluminescence immunoassay. <b><i>Results:</i></b> Obese subjects had significantly higher SBP, DBP, waist and hip circumferences, waist-to-hip ratio, waist-to-height ratio, ALT, γ-GT, triglycerides, apolipoprotein-B, insulin, and HbA_1C concentrations than overweight and normal-BMI subjects. HCC did not differ significantly among the three groups of subjects (mean ± SEM: 8.74 ± 0.43 vs. 8.88 ± 0.52 vs. 9.33 ± 0.72, all <i>p</i> &#x3e; 0.05). No significant association was noted between HCC and cardiometabolic or body composition parameters. HCC was significantly higher in prepubertal girls than prepubertal boys (9.45 ± 0.38 vs. 7.35 ± 0.39, <i>p</i> = 0.007). <b><i>Conclusion:</i></b> In our study, overweight and obesity was not associated with elevated HCC. Furthermore, no association was found between HCC with cardiometabolic parameters and fat mass. Further studies are required to delineate the association between overweight/obesity and HCC.