Background: A high index of suspicion for nerve palsy is essential in the setting of a displaced supracondylar humerus fracture (SCHF) with careful attention to the examination. We hypothesize that nerve injuries are more prevalent in higher energy type III and flexion SCHFs compared with type II fractures. Methods: A retrospective review was performed of 1085 operatively treated SCHFs in pediatric patients, aged 0 to 14 years, between January 1, 2015 and December 31, 2018. There were 979 patients eligible for analysis. Exclusion criteria included follow-up <3 weeks, polytrauma, pathologic fracture, and prior fracture of the ipsilateral elbow. Results: The overall rate of nerve injury was 10.6% (104/979). A significant difference in the rate of nerve palsy was identified between fracture types: 0.9% type II, 19.3% type III, and 10.7% flexion type SCHFs (P<0.001). Median nerve palsy was the most common (n=65). An increased rate of ulnar nerve palsy was observed in flexion type SCHFs. The rate of nerve palsy was higher in the medial pin group (14.9%, P=0.035) but no significant association with iatrogenic ulnar nerve palsy was present. In type III and flexion SCHFs, operative time >60 minutes (P=0.023) and the need for open reduction (P=0.012) were significantly associated with postoperative nerve palsy. Referral to therapy was required in 30.8% of patients with a nerve palsy compared with 7.9% of patients without (P<0.001). Conclusion: Longer operative times, need for open reduction, and significantly higher rates of nerve palsy among type III and flexion SCHFs are best explained by the unstable nature of the fracture and greater degree of soft tissue trauma. Given prolonged duration of follow-up and more frequent need for therapy demonstrated in patients with a nerve palsy, these data can be used to improve counseling for families and patients after displaced SCHF. Level of Evidence: Level III—retrospective comparative study.