Background: Posterolateral rotatory instability (PLRI) of the elbow can lead to pain, recurrent dislocations, and, in the worst-case scenario, disability. Purpose: To report the indications, outcomes, and complication rates of lateral ulnar collateral ligament (LUCL) reconstruction for chronic PLRI of the elbow. Study Design: Systematic review. Methods: This systematic review was registered with PROSPERO and performed in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The review entailed 17 studies that included 168 patients with isolated LUCL reconstruction for chronic PLRI. Patients with concurrent medial collateral ligament reconstruction were excluded. The primary outcome measures were patient characteristics, indication for surgery, surgical technique, functional outcomes, and complications. Results: Chronic PLRI commonly occurred after a previous traumatic injury (n = 168). Of these, there were 119 simple instabilities (no fracture) and 33 complex instabilities (associated fracture). In 11 patients, PLRI was iatrogenic. The cause was unknown in 5 patients. Grafts used were autograft (n = 102; 61%), allograft (n = 18; 11%), synthetic graft (n = 15; 9%), and unknown (n = 33; 20%). The most common surgical technique was a docking procedure or a modification of this (n = 145; 86%). Other techniques included suture anchors (n = 18; 11%), nonanatomic (n = 1; 0.6%), and unknown (n = 4; 2%). There were 45 complications reported in 37 patients (22%). The most frequent complication was recurrent instability (21/138; 15%). No other major complications were reported. The rate of recurrent instability was significantly higher in revision reconstructions (6/15 elbows; 40%) compared with primary reconstructions (15/123 elbows; 12.2%) ( P = .005). The mean Mayo Elbow Performance Score and abbreviated Disabilities of the Arm, Shoulder and Hand score were 87.5 (range, 40-100) and 18.8 (range, 0-77), respectively. Of the patients in whom range of motion was measured, 134 of 144 patients (93%) regained a functional range (30L–130L). Conclusion: LUCL reconstruction for chronic PLRI proved a reliable method of reconstruction, save for the moderate rate of recurrent instability, which was highest in revision reconstructions.