Full-thickness mucous membrane is an acceptable autogenous graft to replace the deficient conjunctiva resulting from intrinsic disease, surgical resection for carcinoma, or reconstruction of contracted sockets. The mouth provides an excellent source of mucous membrane graft material with few donor site complications. However, we encountered four cases of donor site complications after full-thickness mucous membrane grafting. All cases involved submucosal scarring with contracture. Because the inner aspect of the mouth is a multicontoured surface, the submucosal scarring resulted in web formation and limitation of movement of the mandible or lip. In two cases, we resected submucosal fibrotic scar tissue and designed a standard or multiple Z-plasty to release mucosal tension. This allowed a return to normal oral function.