Intra-articular ganglion cysts of the knee are a rare occurrence in pediatric patients, particularly involving the anterior cruciate ligament (ACL). Only a handful of case reports have been documented in the medical literature, highlighting the rarity of this condition. Patients with intra-articular cysts often experience knee discomfort and mechanical symptoms like locking of the knee.We present the case of a 13-year-old boy who had a unilateral intra-articular ganglion cyst of the ACL in his left knee. To diagnose and treat the cyst, we conducted radiographs and MRIs, and arthroscopic drainage was performed, resulting in a successful cyst decompression.Our case report provides an overview of the pathogenesis, diagnostic methods, treatment options, and complications of treatment for intra-articular cysts of the ACL. It highlights the rarity of this condition in pediatric patients and underscores the importance of prompt diagnosis and appropriate management.