To report an outcome study of 123 consecutive patients treated by graded unilateral medial rectus recession for small to moderate angle esotropia over an 8-year period with a minimum follow-up of 6 months. The records of patients who underwent unilateral medial rectus recession for constant esotropia measuring 15 to 35 prism diopters (PD) were reviewed. Unilateral medial rectus recession of 5.0, 5.5, 6.0, 6.5, and 7.0 mm was performed for 15 to 18, 19 to 20, 21 to 25, 26 to 30, and 31 to 35 PD of esodeviation, respectively. Postoperative follow-up was at least 6 months. Successful alignment was defined as ±5 PD of orthophoria in primary and lateral gaze while viewing distant and near accommodative targets. The eyes of 96.8% of the patients were successfully aligned and the average deviation corrected was 17.33 ± 1.16 PD for 5 mm, 18.57 ± 2.51 PD for 5.5 mm, 23.67 ± 4.91 PD for 6 mm, 26.68 ± 3.87 PD for 6.5 mm, and 31.93 ± 3.26 PD for 7 mm unilateral medial rectus recession at 6-month follow-up. Seventy-four patients (83.2%) with more than 6 months of follow-up achieved successful alignment, 14 (15.7%) were under-corrected, and 1 (1.1%) was overcorrected. Successful alignment was achieved in most esotropic patients treated by the graded unilateral medial rectus recessions. The surgical guidelines provide a reference for the treatment of small to moderate angle esotropia.