Background: Good nutrition knowledge is a modifiable determinant of dietary behaviours and contributes to strengthen the skills and abilities needed to resist the environmental influences leading to poor dietary habits among adolescents. Objectives were to assess the nutrition knowledge of in-school adolescents in Sokoto, Nigeria and associated factors. Methods: A cross-sectional survey of adolescents selected through multistage random sampling. Data was obtained using pre-tested semi-structured interviewer administered questionnaire. Data was analyzed using IBM® SPSS version 25. Results: A total of 389 subjects were recruited with a mean age of 15.46±1.67 SD and most of them 231 (59.4%) were females. Most 300 (77.1%) of the participants were Hausa, 350 (90%) were Muslims, 278 (71.5%) were from the senior class, and majority 360 (92.5%) resided in urban areas. A large proportion 312 (80.2%) of the participants had good knowledge about classes of food. Only 40 (10.3%) had good knowledge of energy rich food. Two hundred and ninety-eight (76.6%) and 89 (22.9%) had knowledge on high protein diet and good fat diet respectively. Only 107 (27.5%) had good knowledge on minerals and vitamins that are good for bone development. Majority 317 (81.5%) and 341 (87.7%) of the respondents knew eating balanced diet is important and could prevent diseases, respectively. Age category (p=0.007) was the only factor that predicted nutrition knowledge. The main source of nutrition information of the adolescents was teachers 336 (86.4%). Conclusions: Respondents had good knowledge of classes of food. There is however, the need to emphasize on teaching adolescents in the study area about specific nutrient providing meals such as energy rich food, good fat, minerals and vitamins.