Purpose The purpose of this study was to determine the effect of unilateral large lateral rectus (LR) recession on head turn and horizontal ocular deviation in patients with unilateral exotropic Duane retraction syndrome. Patients and methods This was a prospective, interventional study of 10 consecutive patients with unilateral exotropic Duane retraction syndrome associated with contralateral head turn. All patients underwent large (8.5–10 mm) unilateral LR recession on the affected eye. All patients were followed up for at least 6 months. Preoperative and postoperative ocular deviation, angle of head turn, stereoacuity, and severity of limitation in abduction and adduction were recorded and analyzed. Results Mean head turn decreased from 30.5±9.56° (range, 15°–40°) to 6.5±4.74° (range, 0°–15°) (P