Anemia remains an important public health problem among adolescent girls, while the success of iron supplementation programs depends substantially on adherence. Knowledge and family support are behavioral factors that may strengthen adherence. To analyze the association between knowledge of anemia and family support with adherence to iron supplementation among adolescent girls. This quantitative analytical cross-sectional study included 106 respondents selected using purposive sampling from a population of 144 female students.Data were collected using validated and reliable questionnaires assessing knowledge, family support, and adherence, with hemoglobin assessment included in the study protocol. All questionnaire items demonstrated acceptable validity (r = 0.361–0.842; p < 0.05), with good internal consistency (Cronbach’s α = 0.781–0.912).. Univariate analysis described variable distributions, while associations between knowledge and family support with adherence were analyzed using the chi-square test and Odds Ratios (ORs) with 95% confidence intervals (CIs). Overall, 54.7% of respondents had good knowledge and 53.8% were reported to be adherent to iron supplementation. The reported analysis identified a significant association between knowledge and adherence (p=0.001; OR=6.400; 95% CI 1.930–21.223) and between family support and adherence (p<0.001; OR=8.542; 95% CI 2.872–25.403). Knowledge and family support were associated with adherence to iron supplementation. Family support showed the larger reported measure of association. These findings support strengthening school-based supplementation strategies through anemia education, reminders, and family engagement. However, the reported cross-tabulations and OR estimates should be verified against the raw dataset before submission because of internal inconsistencies in the source tables.