While the majority of individuals recover completely from a concussion within 2 weeks, some people experience symptoms beyond this timeframe. There is no consensus definition for this syndrome, making scientific study a challenge. A commonly used term to describe this condition is persistent post-concussive symptoms (PPCS). Persisting symptoms after concussion (PSaC) is a newer term that has been used to describe symptoms after a concussion has healed. As this term is not yet widely accepted in the literature, we will use PPCS in this chapter. PPCS is likely caused by a combination of physiologic derangement, neurologic alterations, abnormalities of the vestibulo-ocular system, and psychological factors, among others. Evaluation can be done by examining the different systems contributing to symptoms, and focused treatments can be directed at abnormalities in certain areas. Complications of PPCS may include second impact syndrome, chronic traumatic encephalopathy (CTE), and depression/suicide, although these are also widely debated.