BACKGROUND: The optimal treatment strategy for the surgical management of femur fractures and non-unions remains unknown. The aim of this study is to assess union rates, complications and outcome after femoral double plating. Treatment of shaft, distal, periprosthetic fractures and pathological proximal femur fractures as well as femoral non-unions with double plating were evaluated. METHODS: A systematic review according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement was conducted. Published literature reporting on the treatment and clinical outcome of femoral fractures and non-unions with double plating was identified. In total, 24 studies with 436 cases of double plating, 64 cases of single plating, 84 cases of intramedullary nailing (IM), and 1 interfragmentary screw treatment met the inclusion criteria of this systematic review. The evaluated literature was published between 1991 and 2020. RESULTS: Double plating of femoral fractures achieved high healing rates and few complications were reported. It displayed significantly less intraoperative haemorrhage, shorter surgery time reduced risk of malunion in polytraumatised patients when compared to IM. Fracture healing rate of double-plating distal femoral fractures was 88.0%. However, there were no significant differences regarding fracture healing, complication or functional outcome when compared to single plating. Treatment of periprosthetic fractures with double plating displayed high healing rates (88.5%). Double plating of non-unions achieved excellent osseous union rates (98.5%). CONCLUSIONS: The literature provides evidence for superior outcomes when using double plating in distal femoral fractures, periprosthetic fractures and femoral non-unions. Some evidence suggests that the use of double plating of femoral fractures in polytraumatised patients may be beneficial over other types of fracture fixation. LEVEL OF EVIDENCE: IV.