Abstract: The nutritional transition in developing countries may lead to imbalances in the growth and nutritional status of adolescents in such countries - events that could result in improper maturation and morbidity in adult life. This study seeks to determine the patterns of physical growth and nutritional status of adolescents living in a low income semi-urban town in Nigeria. Anthropometric data from six hundred and twenty five (625) secondary school students aged 10-19 years (adolescents) were collected and their Body Mass Index (BMI) calculated. Their heights and weights were compared to those of a reference population. Outcome measures for nutritional status were proportion of the population that is stunted (height-for-age < 3rd percentile of the reference data), thin and overweight/obese (BMI-for-age < 5th and > 85th percentiles of the reference data respectively). The girls matched the heights of half of the reference population at all ages, but the boys did not. From age fourteen years, the boys weighed less than half of the reference population while the girls matched or weighed more than the reference population. Under-nutrition was found to affect 19.36% of the population (with stunting accounting for 84.47% of this group), while 13.12% of the population were overweight/obese. The prevalence of thinness and stunting were higher in boys than in girls. Boys were also slightly more obese than the girls. Under- and over-nutrition co-exist in the population and affect more boys than girls. There is an urgent need to address these problems in preventive and curative health care programmes.