Basal cell carcinoma (BCC) is the most prevalent malignant periocular tumor throughout the world, with a higher incidence in the age group above 60. Excessive exposure to Ultraviolet radiation is one of the well-known risk factors. Periocular BCCs more frequently occur on the lower lid and medial canthus. If periorbital invasion occurs, orbital exenteration is essential. In this report, we present a case of a 72-year-old man with recurrent neglected BCC of the medial canthus of the right eye with infiltration of the medial rectus muscle of the right orbit and right ethmoid air sinus, treated with Intensity-Modulated Radiation Therapy (IMRT) modality. The course of radiotherapy resulted in rapid tumor regression, with a major partial response after a one-year follow-up with acceptable toxicities. We believe that radiotherapy is an alternative treatment option to preserve anatomy in frail elderly patients unfit for surgery. As far as we know, our report is the first to report using IMRT in treating large advanced periocular tumor.