Although recent biomechanical studies have reported mechanical superiority of augmented anterior talofibular ligament reconstruction using suture-tape, clinical evidence regarding the efficacy of suture-tape augmentation is still insufficient. This prospective study was performed to evaluate the outcomes of the modified Broström procedure augmented with suture-tape for chronic ankle instability with generalized ligamentous laxity, which has been known to be a poor prognostic factor for anatomic ligament repair. Twenty-eight patients with generalized ligamentous laxity were followed for more than 2 years after the augmented modified Broström procedures for chronic ankle instability. Generalized ligamentous laxity was defined as a Beighton score ≥4 points. The clinical evaluation consisted of the Foot and Ankle Outcome Score (FAOS) and Foot and Ankle Ability Measure (FAAM) score. Measurement of talar tilt angle and anterior talar translation was obtained from stress radiographs to evaluate mechanical ankle stability. FAOS and FAAM scores had significantly improved from preoperative average 63.2 and 54.3 points to 90.6 and 89.5 points at final follow-up, respectively ( P < .001). Talar tilt angle and anterior talar translation had significantly improved from preoperative average 16.2° and 12.1 mm to 3.6° and 4.2 mm at final follow-up, respectively ( P < .001). Preoperative side-to-side comparison with stress radiographs was significantly different, but this returned to within nonstatistical differences at final follow-up, respectively ( P = .105, .532). Although 6 patients sustained an ankle sprain after operation, only 1 patient (3.6%) showed a recurrence of subjective and mechanical instability. Suture-tape augmentation for the modified Broström procedure appears to be an effective operative alternative for chronic ankle instability with generalized ligamentous laxity. As one of the methods to improve the clinical outcomes in patients with relative contraindications of the modified Broström repair, this procedure provided reliable stability with the advantages of anatomic ligament repair through the augmentation using suture-tape. Level IV, prospective case series.