The Diagnostic and Statistical Manual of Mental Disorders (i.e., DSM-5) currently recognizes three primary eating disorders: anorexia nervosa, bulimia nervosa, and binge eating disorder. The origins of eating disorders are complex and remain poorly understood. However, emerging research highlights a dimensional approach to understanding the multifactorial etiology of eating disorders as a means to inform assessment, prevention, and treatment efforts. Guided by research published since 2011, this review summarizes recent findings elucidating risk factors for the development of eating disorders across the lifespan in three primary domains: (1) genetic/biological, (2) psychological, and (3) socio-environmental. Prospective empirical research in clinical samples with full-syndrome eating disorders is emphasized with added support from cross-sectional studies, where relevant. The developmental stages of puberty and the transition from adolescence to young adulthood are discussed as crucial periods for the identification and prevention of eating disorders. The importance of continuing to elucidate the mechanisms underlying gene by environmental interactions in eating disorder risk is also discussed. Finally, controversial topics in the field of eating disorder research and the clinical implications of this research are summarized.