Nutrition indictors in estate sector in Sri Lanka are low. This study estimated prevalence of undernutrition and associated factors among 13-to 16-year-old females in estates of Haliela in Sri Lanka. In a community-based study, 524 adolescents were assessed for height and weight, and information related to associated factors was obtained through an intervieweradministered questionnaire. Prevalence of undernutrition was 39.1% (95% confidence interval = 34.9% to 43.3%). It showed a decreasing trend with increasing age. Among sociodemographic, sanitary/hygienic and diet/food-related factors, multivariate analysis showed that low socioeconomic strata (odds ratio [OR] = 35.0), low dietary diversity (OR = 1.6), food purchase at each meal/daily (OR = 2.1), and "poor" food availability (OR = 6.6), were associated with adolescent undernutrition. Undernutrition among female adolescents in estates is a public health problem. Improving availability of food to estate adolescent females through targeted programs and reducing poverty among estate dwellers are recommended to overcome the problem.