OBJECTIVE This study aimed to determine the prevalence and the temporal trend in overweight, as well as their relationship with sociodemographic factors in adolescents from northeastern Brazil. SUBJECTS AND METHODS We analyzed data from two similar school-based, cross-sectional epidemiological studies conducted in 2005 (n = 2,768) and 2009 (n = 2,776), with public and private high school students of both sexes, aged 14 to 18 years, in João Pessoa, state of Paraiba, Brazil. Sociodemographic information (sex, age and economic class), body weight (kg) and height (cm) were self-reported by the students. Body mass index was classified according to International Obesity Task Force criteria. RESULTS There was a significant increase of three percentage points in overweight prevalence from 2005 (10.1%; CI95%: 8.9-11.3) to 2009 (13.1%; CI95%: 11.4-15.5), which was of greater magnitude in males (5.0%; p < 0.001) than in females (1.8%; p = 0.085). Adjusted analysis showed that the Odds Ratio for an adolescent to show overweight in 2009 compared with 2005 was 1.34 (CI95%: 1.13-1.60), which was also greater in males (OR = 1.45; CI95%: 1.15-1.83), in adolescents aged 16 years (females - OR = 3.01; CI95%: 1.62-5.55), and in those from the middle economic class (males: OR = 1.47; CI95%: 1.03-2.23; females: OR = 1.59; CI95%: 1.01-2.53). CONCLUSIONS Prevalence of overweight in adolescents was high, and showed an increasing trend, particularly in males who belonged to the middle economic class.