Background: Surgical repair of clavicle fractures is being employed more frequently, although most fractures are still treated conservatively. Both can result in nonunion. Current treatments for clavicle nonunion include open reduction with internal fixation (ORIF) plating without bone graft, ORIF plating with bone graft, and intramedullary pin fixation.Methods: We performed a systematic review and meta-analysis of studies reporting outcome, complication, and reoperation rates following surgical treatment for clavicle nonunion. Subgroup analysis was undertaken for outcome and complication rates between single plating and intramedullary pin fixation, bone graft use, and nonunion time length definition.Results: Fifty-three studies met inclusion criteria (1,258 clavicle nonunions). Mean clinical follow-up was 2.6 years. Seventy-two percent of nonunions were of the middle third, 1% were proximal third, 12% were distal third, and 15% were not reported. Forty-eight percent of nonunions were atrophic or oligotrophic and 17% were hypertrophic (35% not reported). Mean time to union was 13.6 weeks. Ninety-five percent of patients achieved union after the primary nonunion surgery. Overall complication rate was 17%. Singleplating fixation had significantly faster union time (15.2 vs. 19.8 weeks), lower reoperation rate (23% vs. 37%), and hardware removal rate (20% vs. 34%) than intramedullary pin fixation. Bone graft had significantly lower rates of delayed union (0.6% vs. 3.6%) but higher complication (15% vs. 8%) and reoperation rates (29% vs. 14%) than the other groups. Studies that defined nonunion after 3 months had significantly faster union times than the 6-month studies (13 vs. 16 weeks). The 3-month group had a significantly lower overall complication rate (12% vs. 25%) and hardware/fixation failure rate (3% vs. 5.5%) than the 6-month group.