ObjectiveSeveral studies have been published regarding the treatment of medial ulnar collateral ligament (MUCL) injuries for professional overhead athletes. However, there is a paucity of data regarding non‐professional athletes. The aim of this systematic review was to compare the rate of outcome scores and complications of conservative versus operative treatments both in non‐professional athletes and in non‐sport‐related trauma patients with MUCL lesions.MethodsA systematic review of the published literature was performed by applying the PRISMA guidelines. A search was conducted using three databases: Medline, Science Direct, and Web of Science. The keywords used were “ulnar collateral ligament injury,” “elbow,” “surgery,” and “conservative treatment”. Patients were divided into three groups: patients who underwent conservative treatment (C‐group), surgical treatment (S‐group), and surgery after a failed conservative treatment (C&S‐group). Clinical outcomes were analyzed: Disability of Arm, Shoulder and Hand (DASH), Conway scale, Carson score, and Kerlan–Jobe Orthopaedic Clinic score (KJOC).ResultsA total of 15 studies were included, evaluating 513 patients. Although good and excellent outcomes were found for most patients during daily and/or sport activities, independently of the type of treatment, the C‐group had better results. Excellent results were found in 98.8% of the C‐group, in 88.1% of the S‐group, and in 87.7% of the C&S‐group. The complication rate in the C‐group was statistically higher compared to the S and C&S groups (P < 0.001). However, its complication rate was higher with lower patient satisfaction.ConclusionsThere is insufficient evidence to establish statistically significant differences in the effects of conservative versus surgical treatments on the functional outcomes of patients with MUCL lesions. However, a period of rehabilitation therapy and the functional request of the single injured subject are useful to discern which patients genuinely require MUCL surgical repair.