Body image and eating concerns are prevalent among early adolescent girls, and associated with biological, psychological and sociocultural risk factors. To date, explorations of biopsychosocial models of body image concerns and disordered eating in early adolescent girls are lacking. A sample of 488 early adolescent girls, mean age = 12.35 years (SD = 0.53), completed a questionnaire assessing depressive symptoms, self-esteem, body mass index (BMI), sociocultural appearance pressures, thin-ideal internalization, appearance comparison, body image concerns and disordered eating. Structural equation modelling was conducted to test a hypothetical model in which internalization and comparison were mediators of the effect of both negative affect and sociocultural influences on body image concerns and disordered eating. In addition, the model proposed that BMI would impact body image concerns. Although the initial model was a poor fit to the data, the fit was improved after the addition of a direct pathway between negative affect and bulimic symptoms. The final model explained a large to moderate proportion of the variance in body image and eating concerns. This study supports the role of negative affect in biopsychosocial models of the development of body image concerns and disordered eating in early adolescent girls. Interventions including strategies to address negative affect as well as sociocultural appearance pressures may help decrease the risk for body image concerns and disordered eating among this age group.