ObjectiveTo evaluate the efficacy of a three‐dimensional (3D)‐printed, patient‐specific reduction system for aligning diaphyseal tibial fractures stabilized using minimally invasive plate osteosynthesis (MIPO).Study designProspective clinical trial.Sample populationFifteen client owned dogs.MethodsVirtual 3D models of both pelvic limbs were created. Pin guides were designed to conform to the proximal and distal tibia. A reduction bridge was designed to align the pin guides based on the guides' spatial location. Guides were 3D printed, sterilized, and applied, in conjunction with transient application of a circular fixator, to facilitate indirect fracture realignment before plate application. Alignment of the stabilized tibiae was assessed using postoperative computed tomography scans.ResultsMean duration required for virtual planning was 2.5 h and a mean of 50.7 h elapsed between presentation and surgery. Guide placement was accurate with minor median discrepancies in translation and frontal, sagittal, and axial plane positioning of 2.9 mm, 3.6°, 2.7°, and 6.8°, respectively. Application of the reduction system restored mean tibial length and frontal, sagittal, and axial alignment within 1.7 mm, 1.9°, 1.7°, and 4.5°, respectively, of the contralateral tibia.ConclusionDesign and fabrication of a 3D‐printed, patient‐specific fracture reduction system is feasible in a relevant clinical timeline. Intraoperative pin‐guide placement was reasonably accurate with minor discrepancies compared to the virtual plan. Custom 3D‐printed reduction system application facilitated near‐anatomic or acceptable fracture reduction in all dogs.Clinical significanceVirtual planning and fabrication of a 3D‐printing patient‐specific fracture reduction system is practical and facilitated acceptable, if not near‐anatomic, fracture alignment during MIPO.