BACKGROUND: Ankle sprain is one of the most frequently encountered musculoskeletal injuries; however, the efficacy of acupuncture in treating ankle sprains remains uncertain. We therefore performed a systematic review to evaluate the evidence regarding acupuncture for ankle sprains. METHODS: We searched 15 data sources and two trial registries up to February 2012. Randomized controlled trials of acupuncture were included if they involved patients with ankle sprains and reported outcomes of symptom improvement, including pain. A Cochrane risk of bias assessment tool was used. Risk ratio (RR) or mean difference (MD) was calculated with 95% confidence intervals (CIs) in a random effects model. Subgroup analyses were performed based on acupuncture type, grade of sprain, and control type. Sensitivity analyses were also performed with respect to risk of bias, sample size, and outcomes reported. RESULTS: Seventeen trials involving 1820 participants were included. Trial quality was generally poor, with just three reporting adequate methods of randomization and only one a method of allocation concealment. Significantly more participants in acupuncture groups reported global symptom improvement compared with no acupuncture groups (RR of symptoms persisting with acupuncture?=?0.56, 95% CI 0.42-0.77). However, this is probably an overestimate due to the heterogeneity (I2?=?51%) and high risk of bias of the included studies. Acupuncture as an add-on treatment also improved global symptoms compared with other treatments only, without significant variability (RR 0.61, 95% CI 0.51-0.73, I2?=?1%). The benefit of acupuncture remained significant when the analysis was limited to two studies with a low risk of bias. Acupuncture was more effective than various controls in relieving pain, facilitating return to normal activity, and promoting quality of life, but these analyses were based on only a small number of studies. Acupuncture did not appear to be associated with adverse events. CONCLUSIONS: Given methodological shortcomings and the small number of high-quality primary studies, the available evidence is insufficient to recommend acupuncture as an evidence-based treatment option. This calls for further rigorous investigations.