Objective: This study aimed to investigate serum visfatin, irisin, and uncoupling protein 1 (UCP1) levels between children with attention deficit and hyperactivity disorder (ADHD) and healthy controls and to discuss how performance on the Stroop Color Test and Serial Digit Learning Test changes with these adipokines. Methods: A total of 45 medication-free children with ADHD and 43 controls aged 8–12 years were enrolled in this study. The serum levels of visfatin, UCP1, and irisin were measured using enzyme-linked immunosorbent assay kits. Results: As a result, in our study, a statistically significant difference was found in UCP1 in the ADHD group compared with the control group, but no significant difference was found in visfatin and irisin levels. An analysis of covariance was also performed for the whole sample, and when controlling for potential confounders, including body mass index, age, and gender, the results did not change. In addition, it was determined that adipokines did not correlate with neuropsychological tests. Conclusion: These findings suggest that UCP1 might be associated with childhood ADHD.