PurposeThis systematic review evaluated the efficacy and safety of autologous chondrocyte implantation (ACI) for chondral defects of the knee in skeletally immature patients. Current available data from patients reported outcome measures (PROMs) and complications were collected, analyzed, and discussed.MethodsThis systematic review was conducted according to the PRISMA guidelines. The following databases were accessed in May 2022: PubMed, Google scholar, Embase, and Scopus. All the clinical studies investigating the efficacy of ACI to manage chondral defects of the knee in skeletally immature patients were accessed. Articles treating patients with surgical procedures other than ACI were not eligible, nor were studies with a follow-up shorter than 12 months.ResultsData from 9 studies (251 procedures) were collected. 32% (80 of 251) of patients were females. The mean length of follow-up was 44.2 ± 29.4 (range, 12–115) months. The mean age of the patients was 16.4 ± 0.7 (range, 15–17) years. The Knee injury and Osteoarthritis Outcome Score (KOOS) and International Knee Document Committee (IKDC) increased of + 41.9/100 (P= 0.003) and + 33.2/100 (P=  < 0.0001) points, respectively. The Lysholm Knee Score improved of + 20.6/100 (P= 0.02) points. The Visual Analogue Scale (VAS) for pain reduced of − 3.6/10 (P= 0.004) points. The Tegner scale did not show any statistically significant improvement from baseline to follow-up (P= n.s.). The rate of graft hypertrophy was 12.5% (5 of 40 patients), and the rate of failure 5.6% (8 of 142 patients).ConclusionACI for chondral defects of the knee is effective to improve PROMs in skeletally immature patients. The safety profile of ACI still remains controversial.Level of evidenceIII.