Impulsivity among individuals with eating disorders (EDs) is associated with severe co-morbidities and poor treatment outcome. However, research investigating the construct of impulsivity in EDs is limited. The objectives of the present study were to characterize multiple dimensions of impulsivity in adolescents with eating disorders (EDs); determine if differences in impulsivity were associated with ED diagnosis and/or broader personality traits; and explore the relationship between impulsivity and etiologically significant variables. Experienced clinicians from a practice-research network provided data on ED symptoms, impulsive characteristics, personality pathology, DSM-IV comorbidity, and family and developmental history for 120 adolescent patients with EDs. Three distinct types of impulsivity were identified: General, Acting Out, and Aggressive/ Destructive. The impulsivity types showed specific relationships to ED diagnosis, broader personality factors, individual histories of adverse (traumatic) events, and family histories of externalizing disorders, supporting the importance of taking assessing and addressing impulsivity in ED research and treatment.