BACKGROUND CONTEXT: In 2008, the Neck Pain Task Force (NPTF) recommended exercise for the management of neck pain and whiplash-associated disorders (WAD). However, no evidence was available on the effectiveness of exercise for Grade III neck pain or WAD. Moreover, limited evidence was available to contrast the effectiveness of various types of exercises. PURPOSE: To update the findings of the NPTF on the effectiveness of exercise for the management of neck pain and WAD grades I to III. STUDY DESIGN/SETTING: Systematic review and best evidence synthesis. SAMPLE: Studies comparing the effectiveness of exercise to other conservative interventions or no intervention. OUTCOME MEASURES: Outcomes of interest included self-rated recovery, functional recovery, pain intensity, health-related quality of life, psychological outcomes, and/or adverse events. METHODS: We searched eight electronic databases from 2000 to 2013. Eligible studies were critically appraised using the Scottish Intercollegiate Guidelines Network criteria. The results of scientifically admissible studies were synthesized following best-evidence synthesis principles. RESULTS: We retrieved 4,761 articles, and 21 randomized controlled trials (RCTs) were critically appraised. Ten RCTs were scientifically admissible: nine investigated neck pain and one addressed WAD. For the management of recent neck pain Grade I/II, unsupervised range-of-motion exercises, nonsteroidal anti-inflammatory drugs and acetaminophen, or manual therapy lead to similar outcomes. For recent neck pain Grade III, supervised graded strengthening is more effective than advice but leads to similar short-term outcomes as a cervical collar. For persistent neck pain and WAD Grade I/II, supervised qigong and combined strengthening, range-of-motion, and flexibility exercises are more effective than wait list. Additionally, supervised Iyengar yoga is more effective than home exercise. Finally, supervised high-dose strengthening is not superior to home exercises or advice. CONCLUSIONS: We found evidence that supervised qigong, Iyengar yoga, and combined programs including strengthening, range of motion, and flexibility are effective for the management of persistent neck pain. We did not find evidence that one supervised exercise program is superior to another. Overall, most studies reported small effect sizes suggesting that a small clinical effect can be expected with the use of exercise alone.