This study aims to analyze the association between demographic, socioeconomic, school-related, and behavioral factors and overweight and obesity in adolescents. The sample included 4,210 public high school students (14-19 years old) in Pernambuco State, Brazil, selected by two-stage cluster sampling. Obesity and overweight were assessed using anthropometric measurements, and the Global School-Based Health Survey was used to collect personal and behavioral data. The cutoff points for defining overweight and obesity were those recommended by the International Obesity Task Force. Prevalence rates for overweight and obesity were 11.5% (95%CI: 10.7-12.8) and 2.4% (95%CI: 1.9-2.9), respectively. Overweight and obesity were more common in males who reported residing in urban areas and were not enrolled in physical education classes. Watching television 3+ hours/day was associated with obesity in females. Reducing TV time and encouraging enrollment in physical education could be effective measures to counteract the growing obesity trends.