Purpose: To evaluate the effect of strabismus surgery in exotropia patients suspected of attention deficit hyperactivity disorder (ADHD). Methods: Parents of 67 exotropia patients answered the Conner Teacher Rating Scale-Revised for suspecting ADHD before and after 3 months of surgery. Patients were divided into 2 groups by preoperative scale scores. Group 1 had scores under 15 and group 2 who were suspected to have ADHD had scores above 15. Characteristics of exotropia and scale score differences were evaluated. Results: Group 1 had 43 patients and group 2 had 24 patients. The ratio of group 2 was significantly higher in boys than in girls (P=0.048). The scale scores increased by 1.30 points in group 1 and decreased by 1.04 points in group 2 but there was no significant difference. Scale scores in each group showed no significant difference according to surgical outcome. Conclusions: In exotropia patients, there was no significant change in scale scores of ADHD after strabismus surgery.