Ankle sprain is one of the most common sports-related injuries and can lead to recurrences and chronic ankle instability (CAI). In the acute phase, ankle sprain patients experience mostly pain, limited ankle mobility, and reduced ankle muscle strength. CAI patients have a history of their ankle “giving way” and/or “feeling unstable,” after at least one significant ankle sprain. They continue to suffer from pain and impaired performance during functional tasks. Both acute ankle sprains and CAI have a negative influence on daily life activities such as walking, sports-related activities such as jump landings, as well as on patients’ perception of health and function. Functional deficits should be carefully assessed for appropriate clinical decision making and to propose the most suitable, individualized (physiotherapeutic) intervention. Acute ankle sprains are first treated according to the rest, ice, compression, and elevation (RICE) protocol. Nonsteroidal anti-inflammatory drugs may also be recommended for pain management. A short period of immobilization by means of a lower leg cast can facilitate rapid decrease in pain and swelling. Afterward, functional exercise therapy is recommended. In the case of CAI, patients should wear external ankle support during sporting activities to reduce the risk of recurring sprains and undergo exercise therapy including balance and muscle strengthening exercises. New technologies could be implemented in future rehabilitation programs in order to offer athletes greater flexibility in terms of training time and more varied, sports-related, exercises at home.