Related to the cognitive-behavioral theory of eating disorders, body checking has gained increasing recognition as both a maintaining factor for eating disorders and an important target for treatment. However, it is unclear whether body-checking behaviors contribute to the development of disordered eating, or if these behaviors develop as a response to experiencing eating disorder thoughts and behaviors. This study aims to examine the relationships between body-checking behaviors and eating disordered thoughts and behaviors in adolescent females and males in the community over time.