The objective of the current study was to conduct a longitudinal study of adolescent girls to determine how temperament, attitudes toward shape and weight, life events, and family factors might contribute to the growth of clinically significant importance of shape and weight, assessed using the Eating Disorder Examination (EDE). Time 1 data were available from 699 female twins (M age = 13.96 years) and 595 parents, and approximately 1.15 years later (Time 2) the twins completed the EDE again (M age = 15.10 years). Twins were treated as singletons in the analyses. Time 1 importance of shape and weight was a significant predictor of Time 2 lifetime disordered eating behaviors. Seven Time 1 variables were significant univariate predictors of Time 2 importance of shape and weight. In multivariate analyses, fathers' sensitivity to reward was the only significant predictor of growth of Time 2 importance of shape and weight. Some support was found for established risk factors of disordered eating risk, while the multivariate analyses highlight the importance of developing conceptualizations of eating disorder etiology beyond the individual level.