After haematopoietic stem cell transplantation and a history of GVHD, the risk of developing secondary malignancies, including oral cancer, is higher. This risk increases with time post-transplantation; therefore, pediatric patients undergoing HSCT, who have long-term survival chances, are in a high-risk category. The aim of this review is to provide data on HSCT, GVHD, clinical manifestations, histological features and treatment of oral cancer, and outcomes in HSCT pediatric patients, affected by oral GVHD, who have been developed OSCC. Descriptive statistics were used to validate data. Fifteen studies on a total of 33 patients were selected. Data on oral cancer showed that the tongue was the most frequently involved site (13 pts; 39.39%), followed by the floor of the mouth (4 pts; 12.12%), and buccal mucosa (4 pts; 12.12%). Oral squamous cell carcinoma was the histological feature reported. There were 19 (57.58%) deaths occurring between 2 and 46.5 months after OC diagnosis. Eleven patients survived with a median follow-up of 34 months. Considering the high risk of developing oral cancer, a conventional oral examination every 6 months is recommended for HSCT pediatric patients who have developed GVHD.