The aim of this study was to assess the prevalence of underweight, normal body weight, overweight, obesity and abdominal obesity in Greek adolescents. A nationally representative sample of 37 344 Greek adolescents, aged 12–19 years old, was recruited from schools throughout the country during 2010–2012. Body weight, stature and waist circumference were measured. The prevalence of each weight status category was defined according to the International Obesity Task Force criteria and abdominal obesity was diagnosed according to the International Diabetes Federation. One-third of the participants were either overweight or obese. Among adolescent boys, the prevalence of underweight was 3.3%, 27.9% were overweight and 8.9% were considered obese. Among the girls, 5.8% of the population were underweight, 19.4% were considered overweight and 6.0% obese. Abdominal obesity was diagnosed in 9.1% of the sample (8.9% of the boys and 9.2% of the girls). In 4.5% of the population, simple and central obesity coincided. The pooled prevalence of overweight and obesity as well as the rate of abdominal obesity appear to level off during the course of adolescence. The results indicate a high prevalence of overweight among Greek adolescents.