Inadequate food security contributes to poor health outcome for all, including adolescent girls. The study aims at determining the level of food security and hygiene among adolescent girls. A school-based cross-sectional study was carried out among adolescent girls aged 10 to 19 years old from six schools in Maiduguri Metropolitan Council, Borno State. The instrument for data collection was a questionnaire using KoBoCollect Toolbox between June and July 2019. Multivariable logistic regression was used to identify the predictors of food security and hygiene among respondents. A majority of the respondents (73.5%) were in a very low food security level. Three factors were significantly associated with food security level, these included schools (p = 0.007), age of mother (p = 0.004), and occupation of mother (p < 0.001). School (p = 0.003), age (father p = 0.017; mother; p = 0.012), hygiene (p = 0.005), and occupation of mother (p = 0.002) were predictors of food security. About (46.6%) of respondents had poor hygiene practice, school (p = 0.016) was significantly associated with hygiene practice. School (p = 0.019; and p = 0.005) and food security (p = 0.009) were predictors of hygiene practice. This study reveals a high prevalence of low food security among adolescent girls.