Whiplash-associated disorder (WAD) represents a significant public health problem, resulting in substantial social and economic costs throughout the industrialized world. While many treatments have been advocated for patients with WAD, scientific evidence supporting their effectiveness is often lacking. A systematic review was conducted to evaluate the strength of evidence associated with various WAD therapies. Multiple databases (including Web of Science, EMBASE and PubMed) were searched to identify all studies published from January 1980 through March 2009 that evaluated the effectiveness of any clearly defined treatment for acute (less than two weeks), subacute (two to 12 weeks) or chronic (longer than 12 weeks) WAD. The present article, the third in a five-part series, evaluates the evidence for interventions initiated during the subacute phase of WAD. Thirteen studies that met the inclusion criteria were identified, six of which were randomized controlled trials with ‘good’ overall methodology (median Physiotherapy Evidence Database score of 6). Although some evidence was identified to support the use of interdisciplinary interventions and chiropractic manipulation, the evidence was not strong for any of the evaluated treatments. There is a clear need for further research to evaluate interventions aimed at treating patients with subacute WAD because there are currently no interventions satisfactorily supported by the research literature.