The eyelids form one of the most important elements of the ocular protective system. The eyelashes provide a mechanical screen for dust and debris in the environment. Reflex blinking acts to protect the eyes from harmful external stimuli, such as bright lights and approaching objects. Numerous disease processes, including infection, inflammation and neoplasia, may affect the eyelids. It is therefore important to have a sound anatomical knowledge base to assist in the diagnosis of the many eyelid disorders. This article summarises the most common conditions affecting the eyelids. Eyelid anatomy is outlined briefly in the next section prior to discussion of actual disease processes.