Rates of obesity among adolescents in the United States have increased at a dramatic rate along with the prevalence of weight-related diseases. Between the 1980s and 2014, the prevalence of obesity among adolescent females in the United States increased from approximately 10% to 21%. Although the steep increase in the prevalence of obesity in children (2–11 years) has slowed, the prevalence of obesity in adolescents (12–19 years) continues to increase. Because the obese female adolescent faces medical, psychologic, and reproductive health challenges, early intervention is imperative in preventing short-term and long-term morbidity. The obstetrician–gynecologist who is knowledgeable about the behavioral and environmental factors that influence obesity may be better able to educate parents, guardians, and adolescents and advocate for programs that increase physical activity and improve nutrition. The obstetrician–gynecologist should be able to identify obese adolescents, particularly those at risk of comorbid conditions. They may have the opportunity to initiate behavioral counseling, participate in multidisciplinary teams that care for overweight and obese adolescents, and advocate for community programs to prevent obesity.