Web-based interventions are an emerging approach to managing diabetes in Korea. This review systematically evaluated the effectiveness of these interventions. To identify studies for review, a search of online electronic databases was conducted; the search was guided by the Cochrane processes and Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations. Ten studies published between 2005 and 2015 that met the inclusion criteria were assessed for methodological quality and analyzed. All 10 studies had participants that were Korean adults diagnosed with type 2 diabetes. The analysis revealed that the Web-based interventions under review, which included self-care management services and decision support systems, improved measures of biophysiological, psychobehavioral, and satisfaction of care outcomes. This review found strong evidence of the effectiveness of these Web-based interventions in improving glucose controls. Future studies with rigorous research design that study large populations with different age groups and have structured descriptions of interventions are recommended. Nurses and healthcare providers can use the evidence in this review to improve outcomes in diabetes management, and healthcare policy makers can use this review to evaluate whether to adopt these interventions as a care coordination strategy.