The aim of this study was to determine the nutritional status and estimate the prevalence of overweight and obesity among adolescents from different size towns in the Extremadura Region of Spain. A sample of 816 secondary school students of both sexes between 13 and 18 years of age were evaluated. The educative centers selected belonged to different size towns (populations between <5,000 and >60,000 inhabitants). Different anthropometric measures were taken. The percentage of teenagers with overweight and obesity was calculated following national and international standards and compared by town size. Students from rural towns, <5,000 inhabitants, had the lowest values in some of the anthropometric measures; results that are associated with a lower body development. There were differences in the prevalence of overweight and obesity based on the criteria used, but, in general, adolescents from larger towns (>60,000 inhabitants) showed the highest percentages of overweight, whereas rural populations showed the lowest percentages.