This article introduces a novel 3D-printed guide for harvesting subepithelial connective tissue grafts (CTG) from the lateral palate. A digital simulation of CTG harvesting was conducted on a patient’s integrated model using a single incision technique. The model incorporates crucial anatomical information, such as the location of the greater palatine artery and palatal gingival thickness, ensuring that planned incisions avoid critical structures and that a donor tissue of sufficient size (length, width, thickness) is harvested. The guide was designed and 3D-printed to replicate the simulated procedures in the intraoral environment, enhancing surgical precision. During surgery, the CTG palate guide facilitates the successful harvesting of a graft of sufficient size, as preoperatively planned, without causing any complications. This study suggests that the CTG palate guide can reduce complications and surgical time while maximizing the dimensions of the donor tissue.