Functional ankle instability (FAI) is a term used to describe an ankle that easily 'gives way' with activity. There have been many proposed causes of FAI including joint proprioceptive deficiency, muscle weakness, balance control impairments, and delayed muscle reaction time, none of which has proven to be the exclusive cause of FAI. Treatment becomes difficult when the causative factor of the injury is obscure. This systematic review evaluates the clinical trials involving conservative exercise interventions in FAI and examines the changes induced by the exercise treatments to the various potential FAI factors. Sixteen articles describing the active exercise treatment of FAI were analysed using Sackett's levels of evidence and were examined for scientific rigor. From this review, it can be concluded that conservative treatment interventions including balance, proprioceptive and muscle strengthening exercises are effective for patients with FAI in decreasing the incidence of giving-way episodes, improving balance stability, and improving function.