Facial nerve paralysis is the most severe form of cranial neuropathy that causes facial deformity. Late-onset or delayed facial nerve palsy is uncommon following tympanomastoid surgery, although it can occur up to 2 weeks following the procedure. Although pinpointing the specific reason for delayed facial nerve paralysis following tympanomastoid surgery is complex, several variables such as facial nerve injury and/or viral reactivation can play a role. Late facial nerve paralysis after tympanomastoid surgery is caused by exposure of the facial nerve and fallopian canal dehiscence. Late facial nerve paralysis may be produced by viral reactivation and damage to the chorda tympani nerve. This study aims to look at the prevalence, etiology, clinical signs, diagnosis, and current treatment options for delayed facial nerve paralysis following tympanomastoid surgery. The exact cause of delayed facial nerve paralysis after tympanomastoid surgery has significant consequences for therapy and prognosis. The use of steroid and antiviral drugs is helpful for the treatment of the delayed facial nerve paralysis due to viral reactivation. The overall prognosis of the delayed facial nerve paralysis following tympanomastoid operation is good. This article discusses the prevalence, etiopathogenesis, clinical features, diagnosis, and present treatment of late/delayed facial nerve palsy following the tympanomastoid operation.