Conjunctivitis is a common ocular problem that can be seen worldwide and it is still under consideration for global public health. There are many causes of conjunctivitis. Clinically, bacterial conjunctivitis is characterized by purulent ocular discharge, eye crusting or sticky eyes on awakening, foreign body sensation, and conjunctival injection. In more severe cases, chemosis and lid edema may also occur. The involvement is usually unilateral at first but rapidly spreads to the contralateral eye. There are also many tropical infections and disorders that can induce conjunctivitis and those problems are called tropical conjunctivitis. This book discusses several causes of different cases of conjunctivitis. It provides information on the etiology, the diagnosis of different forms of conjunctivitis, and the clinical management.