Gastroparesis is a heterogeneous clinical syndrome. Some patients have debilitating vomiting, weight loss, and dehydration, while others have effortless regurgitation of undigested foods or postprandial distress suggestive of functional dyspepsia. Gastric electrical stimulation (GES) has been proposed as an effective treatment option for patients with gastroparesis refractory to medical therapy. Evidence suggests that the clinically available device, a low-energy high-frequency GES, activates the vagal afferent pathways to influence the central control mechanisms for nausea and vomiting. Myoelectrical effects of the stomach are also involved. The results of randomized controlled trials (RCTs) for adults with diabetic and idiopathic gastroparesis are conflicting. There are no RCTs in adults with chronic unexplained nausea and vomiting (CUNV) with normal gastric emptying or in children with gastroparesis. However, there is increasing evidence from large unblinded studies showing the long-term efficacy in selected adults with gastroparesis. Selection criteria should be based on three categories: (a) underlying etiology, (b) clinical presentation and predominant symptoms, and (c) potential risk for complication. Significant abdominal pain, daily opiate use, and idiopathic gastroparesis are identified as negative predictors of success. Temporary GES has been utilized to identify patients who may benefit from surgical GES, but this strategy has yet to be proven in controlled studies. Objectives for this review are to highlight the mechanisms of action for GES, to look at the evidence for clinical efficacy, and to select patients who are likely to benefit.