BACKGROUND: Chronic ankle instability (CAI) develops in 20% to 40% of patients after ankle sprains because of inappropriate management or a premature return to sports (RTS). Patients become candidates for surgery when nonoperative treatment fails. The results of arthroscopic lateral ligament reconstruction have been shown to be excellent. However, there is no consensus on the RTS criteria in these cases. The Ankle-GO score, which has been validated in lateral ankle sprains, is an evidence-based protocol for RTS. PURPOSE: To evaluate the discriminant and predictive capacity of the Ankle-GO score for RTS after arthroscopic lateral ankle reconstruction. STUDY DESIGN: Cohort study. Level of evidence, 2. METHODS: This prospective multicenter cohort study, conducted between January 2022 and January 2023, evaluated patients with CAI who underwent arthroscopic anatomic lateral ankle ligament reconstruction using gracilis tendon autografts or allografts. The RTS rates at 4 and 6 months postoperatively were the primary and secondary outcomes, respectively. The evaluated variable at both timelines was the Ankle-GO score-a composite of 4 functional tests and 3 questionnaires. The study determined the discriminant validity of the Ankle-GO score for RTS at each timeline-Ankle-GO scores at 4 months for RTS at 4 months; Ankle-GO scores at 6 months for RTS at 6 months. The predictive capacity of the Ankle-GO score at 4 months for RTS at 6 months was also evaluated. RESULTS: A total of 51 patients, with a mean age of 32.8 years, were included, of whom 23 (45%) had returned to sports at 4 months and 39 (76.5%) at 6 months. The mean Ankle-GO score was significantly higher in the group that returned to sports than in the group that did not (12 ± 4.7 vs 8.8 ± 4.7 at 4 months, respectively, = .003; 16.8 ± 3.6 vs 11.3 ± 4.8 at 6 months, respectively, = .002).The predictive capacity of the Ankle-GO score at 4 months for RTS at 6 months was good, with an area under the curve of 0.74 (95% CI, 0.58-0.90; = .005). The optimal threshold was 6 (sensitivity, 95%; specificity, 50%). The odds ratio of RTS when surpassing the Ankle-GO cutoff score was 18.5 (95% CI, 3-113.95; = .002). CONCLUSION: The Ankle-GO score is effective in discriminating the RTS status at 4 and 6 months after lateral ligament reconstruction of the ankle. In addition, the Ankle-GO score at 4 months was also moderately predictive of RTS at 6 months after surgery.