We describe a case of a 13-year-old male patient of Coats' disease who developed sympathetic ophthalmia (SO) following contact diode laser cyclophotocoagulation. There was no history of invasive surgery or any perforating injuries preceding cyclodestructive therapy. The eye had neovascular glaucoma secondary to Coats' disease, which was treated once with contact cyclophotocoagulation. Subsequently, the intraocular pressure slowly decreased, and the eye became phthisical. Intraocular inflammation developed in the fellow eye and SO was suspected, which was confirmed by characteristic findings seen on fluorescein angiography. The case was successfully managed with the help of topical and systemic immunosuppression. Enucleation with silicone ball implantation was performed in the right phthisical eye and specimen was sent for histopathological examination. Histopathology and immunostaining supported the diagnosis of SO.