Purpose To evaluate the clinical results of arthroscopic repair and open Ahlgren-Larsson method in patients with chronic lateral ankle instability. Methods We retrospectively evaluated 60 patients who were operated in our clinic between 2010 and 2018 with the diagnosis of chronic lateral ankle instability. Preoperative and postoperative clinical evaluations were performed with AOFAS ankle-hindfoot score, FAOS, and VAS scores. Results Sixty patients with chronic lateral ankle instability were evaluated. 28 patients were treated with Ahlgren-Larsson method, and 32 patients were treated with arthroscopic repair. Follow-up duration was 35 +/- 12 months for the open surgery group and 19 +/- 2 months for the arthroscopic surgery group. The mean age of the arthroscopy group was 44 +/- 9; the mean age of the open surgery group was 46 +/- 11. There was no significant difference between the groups in terms of demographic features (age, sex, BMI). Postoperative clinical improvement was observed in both groups. There was no statistically significant difference between the groups in terms of functionality. However, there was a statistically significant difference in VAS in terms of pain and patient satisfaction in favor of arthroscopy group. Conclusions Ahlgren-Larsson method and arthroscopic repair technique are safe and effective for chronic lateral ankle instability. Arthroscopic technique may be preferred for pain and patient satisfaction as it is less invasive and less morbid.