Ankle injuries, especially ankle sprains, are a common problem in sports and medical care. Ankle sprains result in pain and absenteeism from work and/or sports participation, and can lead to physical restrictions such as ankle instability. Nowadays, treatment of ankle injury basically consists of taping the ankle. The purpose of this review is to evaluate the effectiveness of ankle braces as a treatment for acute ankle sprains compared with other types of functional treatments such as ankle tape and elastic bandages. A computerized literature search was conducted using PubMed, EMBASE, CINAHL and the Cochrane Clinical Trial Register. This review includes randomized controlled trials in English, German and Dutch, published between 1990 and April 2009 that compared ankle braces as a treatment for lateral ankle sprains with other functional treatments. The inclusion criteria for this systematic review were (i) individuals (sports participants as well as non-sports participants) with an acute injury of the ankle (acute ankle sprains); (ii) use of an ankle brace as primary treatment for acute ankle sprains; (iii) control interventions including any other type of functional treatment (e.g. Tubigrip™, elastic wrap or ankle tape); and (iv) one of the following reported outcome measures: re-injuries, symptoms (pain, swelling, instability), functional outcomes and/or time to resumption of sports, daily activities and/or work. Eight studies met all inclusion criteria. Differences in outcome measures, intervention types and patient characteristics precluded pooling of the results, so best evidence syntheses were conducted. A few individual studies reported positive outcomes after treatment with an ankle brace compared with other functional methods, but our best evidence syntheses only demonstrated a better treatment result in terms of functional outcome. Other studies have suggested that ankle brace treatment is a more cost-effective method, so the use of braces after acute ankle sprains should be considered. Further research should focus on economic evaluation and on different types of ankle brace, to examine the strengths and weaknesses of ankle braces for the treatment of acute ankle sprains.