Episcleritis and scleritis are important causes of acute red eye. Even though both are inflammation of the outer coat of the eyeball, they are clinically, etiologically and morphologically distinct and different. Sclera is an opaque, elastic and resilient tissue of the eye. It can be compared with an incomplete shell comprising approximately 90% (five-sixths) of the outer coat of the eye. Anteriorly it begins at the limbus and terminates at the optic nerve canal posteriorly. It is predominantly composed of collagen and some elastin fibrils and is relatively avascular and acellular. This chapter covers the nomenclature and classification, diagnosis, diagnostic evaluation of scleritis, treatment, and surgical treatment. Diagnosis of scleritis is almost always clinical; however, when the posterior sclera is involved, clinical signs may be less obvious, and imaging studies are necessary to confirm the diagnosis. The primary aim of the treatment of scleral inflammation is to control the inflammatory process to relieve the symptoms and thereby reduce the damage to the eye.