Objective: The aim of this study was to investigate the association between childhood obesity and student academic performance in the classroom setting. Subjects and Methods: A multi-stage cluster random sampling was used to select a representative sample of 1,213 fifth-grade students in male public schools. Height and weight were measured using a standard protocol. Overweight was defined as BMI ≧85th but <95th percentile, while obesity as ≧95th BMI percentile, using growth charts provided by the Centre for Disease Control and Prevention (2000). Data on each student’s academic performance and sociodemographic factors were extracted from school records. Of the 1,213 students, 147 were absent on the day the survey was conducted. Therefore, the analysis was based on 1,066 students. Of the 1,066 students, 67 did not have previous school records because they were new in the school; hence the association between school performance and obesity was based on 999 students. Results: The prevalence of obesity was 186 (17.4%, 95% CI: 15.2–19.9%) while the prevalence of overweight was 232 (21.8%, 95% CI: 19.3–24.4%). There was no significant association between obesity and academic performance after adjusting for sociodemographic factors. Parental education was the most important predictor for high academic performance in the classroom setting. Conclusion: There is no association between obesity and academic performance in the classroom setting among boys in Kuwait. With the lack of evidence of a relationship between childhood obesity and academic performance, using high performance as a measure of success in prevention initiatives cannot be justified.