PURPOSE: To evaluate the outcomes of Harada-Ito surgery in correcting various types of torsional diplopia. METHODS: The medical records of patients who underwent Harada-Ito surgery at two academic institutions were retrospectively reviewed. Data collected included etiology of torsional diplopia, strabismus and torsion measurements, reoperation rate, patient symptoms, and use of prism. Postoperative success was defined as a lack of diplopia in the primary position at distance and downgaze at near with or without prism. Failure was defined as persistent torsional diplopia; partial success was defined as surgical success but with restrictive strabismus in the secondary gaze positions. RESULTS: A total of 26 patients (mean age, 46 years; range, 13-89 years) were included. Of these, 17 had superior oblique palsy. The mean follow-up duration was 2 years (range, 2-60 months). The surgical outcome was success in 73% of patients, partial success in 7%, and failure in 19%. All patients with ≤10° of torsion preoperatively obtained surgical success. Patients in the failure group had higher amounts of preoperative torsion compared to the success group (P = 0.009). The reoperation rate was 23%, including four patients with additional surgery for downgaze esotropia or torsion. One-third of the patients wore a prism immediately after surgery. CONCLUSIONS: Harada-Ito surgery successfully treated torsional diplopia. Patients with ≤10° of preoperative torsion had a better outcome. Downgaze diplopia was a common reason for additional surgery.