OBJECTIVE:To investigate the prevalence and risk factors for disordered weight control behaviors (DWCB) in South Korean adolescents at multiple levels, including individual, family, school, and geographic area. METHOD:We drew participants from the 11th Korea Youth Risk Behavior Web-based Survey, conducted in 2015, with 65,529 adolescents (31,687 girls, 33,842 boys) aged 12-18 years. DWCB was defined as engaging in any of the following behaviors for weight control over the past month: fasting, one-food diet (eating only one food over an extended period of time for weight control), vomiting, and taking laxatives/diuretics/unprescribed diet pills. Sex-stratified four-level multilevel logistic models examined potential predictors of DWCB, including age, body-mass index, puberty, perceived household economic status, parental education, living structure, school type and sex-composition, percentage of students participating in school nutrition programs, and urbanicity. RESULTS:Overall, 6.2% of Korean adolescents (8.9% of girls, 3.7% of boys) exhibited any DWCB. We found significant between-school variation among girls and boys and between-classroom variation among girls. Older age, overweight/obesity, pubertal maturity, high household economic status (vs. mid-range economic status), and vocational schooling (vs. general) were positively associated with DWCB among girls and boys. Low household economic status (vs. mid-range economic status), higher parental education, and coeducational schooling (vs. single-sex) were positively associated with DWCB among girls only. DISCUSSION:The findings suggest that DWCB are prevalent among Korean adolescents across age, sex, and socioeconomic status. Social contextual factors including school and familial environmental factors, as well as individual characteristics, should be considered when developing effective prevention strategies.