Multiple sclerosis can cause a variety of symptoms: changes in sensation (hypoesthesia), muscle weakness, abnormal muscle spasms, or difficulty moving; difficulties with coordination and balance; problems in speech (dysarthria) or swallowing (dysphagia), visual problems (nystagmus, optic neuritis, phosphenes or diplopia), fatigue and acute or chronic pain syndromes, bladder and bowel difficulties, cognitive impairment, or emotional symptomatology (mainly major depression). The main clinical measure in progression of the disability and severity of the symptoms is the Expanded Disability Status Scale or EDSS.

The initial attacks are often transient, mild (or asymptomatic), and self-limited. They often do not prompt a health care visit and sometimes are only identified in retrospect once the diagnosis has been made after further attacks. The most common initial symptoms reported are: changes in sensation in the arms, legs or face (33%), complete or partial vision loss (optic neuritis) (20%), weakness (13%), double vision (7%), unsteadiness when walking (5%), and balance problems (3%); but many rare initial symptoms have been reported such as aphasia or psychosis. Fifteen percent of individuals have multiple symptoms when they first seek medical attention.