Abstract Adolescent undernutrition is a major public health problem in Ethiopia. Inadequate dietary intake of nutrients is the major determinants of undernutrition. However, the adequacy of dietary intake among adolescents was not sufficiently explored. The present study aims to estimate the inadequacy of nutrient intake among adolescent girls in south central Ethiopia. A community-based cross-sectional study was conducted. We assess food and nutrient intake using repeated multiple-pass 24-h dietary recall. The study was conducted in Damot Gale district, Woliyta zone, Southern Ethiopia. Data were collected from 288 female adolescents. The majority of adolescent girls consumed cereals (96⋅9 %) and roots/tubers (75⋅3 %). However, only less than 1 % of them consumed flesh food. The mean energy, carbohydrate, protein and dietary fibre intake of the adolescent girls per day was 1452⋅7 ± 356⋅3 kcal, 305⋅6 ± 72⋅4 g, 35⋅7 ± 13⋅3 g and 18⋅6 ± 8⋅4 g, respectively. The median fat intake was 13⋅3 g (IQR 8⋅8, 19⋅8). The contribution of carbohydrate, protein and fat for the total energy was 80, 10 and 8 %, respectively. The prevalence of inadequate intake of protein was 60⋅9 %. The prevalence of inadequate intake of iron for early adolescents and late adolescents was 82 and 53 %, respectively. The prevalence of inadequate intake of folate was 83⋅9 % and zinc was 58 %. The prevalence of inadequate intake was greater than 90 % for vitamin B12, vitamin C and calcium. The present study found an alarmingly high prevalence of inadequate intake of some nutrients among adolescent girls of Damot Gale district.