We aimed to compare the outcomes and complications of nonoperative and operative treatment for displaced midshaft clavicle fractures in adolescents. Radiological and functional evaluations and complications for 23 patients with nonoperative treatment were compared with those for 18 patients with operative treatment. No nonunion developed in either group. No significant intergroup differences were observed for occurrence of delayed union or time to union (P=0.851 and 0.887, respectively). Both groups showed excellent functional outcomes on the basis of Disabilities of the Arm, Shoulder and Hand scores and Constant Shoulder Scores. Shoulder abduction strength and range of motion were also well restored in both treatment groups. However, recovery of shoulder range of motion was significantly faster in the operative group (mean: 5.3 weeks; range: 4.0-7.0 weeks) than in the nonoperative group (mean: 9.9 weeks; range: 8.0-19.0 weeks) (P<0.001). There were no patients in either treatment group who needed revisional surgery to address complications with functional deficits. Both nonoperative and operative treatments yielded excellent outcomes, without severe complications. On the basis of our results, nonoperative treatment is recommended as a primary treatment option for displaced midshaft clavicle fractures in adolescents. However, operative treatment can be considered in selected patients who require early functional recovery or have a high activity level.