Background: More and more children are undergoing liver transplantation and reaching adolescence, even though they must take immunosuppressant drugs for their entire lives. Objectives: This study aimed to determine the non-adherence rate in liver transplant recipients and identify its potential etiologies. Methods: A cross-sectional survey was performed to assay medication adherence among pediatric liver transplant recipients in Shiraz, Iran. The patients' demographic, socioeconomic, and clinical characteristics were collected via interviews. Medication adherence was assessed using a validated Morisky 8-item Medication Adherence Questionnaire (MMAS-8). Results: A total of 157 patients with a mean age of 12.73 ± 4.02 participated in this study. Based on the Morisky adherence scores, 12.1% (n = 19), 25.5% (n = 40), and 62.4% (n = 98) were categorized as low, moderate, and high adherence groups, respectively. Among all studied variables, and follow-up time after transplant were significantly associated with adherence among children after liver transplantation in Iran. Conclusions: The rate and reported causes of non-adherence are similar to those found in previous studies, which is quite remarkable. Proper instruction, financial aid, and recruitment of new technologies are among the strategies to overcome non-adherence.