Temperament and personality traits, including negative emotionality/neuroticism, may represent risk factors for eating disorders. Further, risk factors may differ by sex. We examined longitudinal temperament/personality pathways of risk for purging and binge eating in youth stratified by sex using data from a large-scale prospective study. Temperament, borderline personality features, sensation seeking, 'big five' personality factors, and depressive symptoms were measured at five time points from early childhood to adolescence in 5812 adolescents (3215 females; 2597 males) in the Avon Longitudinal Study of Parents and Children. We conducted univariate analyses with these predictors of binge eating and purging at 14 and 16 years for total and sex-stratified samples. We used structural equation modeling (SEM) to fit data to a path analysis model of hypothesized associations. Of the total sample, 12.54% engaged in binge eating and 7.05% in purging by 16 years. Prevalence was much greater and increased dramatically for females from 14 years (7.50% binge eating; 2.40% purging) to 16 years (15.80% binge eating; 9.50% purging). For both sexes, borderline personality, depressive symptoms and lower emotional stability predicted eating disorder behaviors; sensation seeking and conscientiousness were also significant predictors for females. SEM identified an 'emotional instability' pathway for females from early childhood into adolescence (RMSEA = 0.025, TLI = 0.937 and CFI = 0.970). Binge eating and purging are common in female and male adolescents. Early temperament/personality factors related to difficulty regulating emotions were predictive of later adolescent eating disorder behaviors. Results have important clinical implications for eating disorder prevention and intervention.