Much advancement has been made in the treatment of knee arthritis. A special area of interest has been the treatment of medial unicompartmental disease. However, patients with isolated lateral compartment arthritis represent a significant subset of the population. Lateral unicompartmental knee arthroplasty (UKA) is performed much less frequently than in the medial compartment and is known to be more technically demanding and less reproducible. Robotic-assisted arthroplasty provides a tool to improve component placement and reproducibility. The purpose of this study is to retrospectively review radiographic and clinical outcomes following robotic-assisted lateral UKA. We retrospectively reviewed 22 patients who underwent robotic-assisted lateral UKA by a single surgeon. Indications consisted of isolated lateral compartment arthritis with correctable valgus deformity and an intact anterior cruciate ligament. Eighteen patients met all inclusion criteria, resulting in 20 lateral UKA. Radiographic and clinical outcomes were evaluated and we found that robotic assistance during lateral UKA provided accurate and reproducible results. Native alignment of the tibia and femur were well maintained in the coronal and sagittal planes, and no overcorrection occurred. The standard deviation of tibial components was 1.8°, indicating strong accuracy and reproducibility. Operative times were increased, but this did not lead to intraoperative complications or slowed progression of postoperative rehabilitation. Robotic-assisted lateral UKA provides a tool for accurate and reproducible component placement with excellent short-term clinical outcomes.