Treatment of snoring and obstructive sleep apnea with oral appliances is a promising alternative to continuous positive airway pressure (CPAP) therapy. Although there is wide variability in appliance design, these devices produce enlargement of the upper airway by advancing the mandible, tongue, or both. Oral appliances effectively reduce snoring in a significant proportion of individuals. In general they are less effective than CPAP in eliminating obstructive sleep apnea, with approximately 50% of individuals experiencing resolution of their obstructive sleep apnea with these devices. Patients with milder disease have greater success with oral appliance therapy than those with more severe disease. A small proportion of patients will experience worsening of their sleep apnea with an oral appliance, and close follow-up after device prescription is mandatory. Patient satisfaction with oral appliances may be better than that with CPAP.