Due to logistical and financial barriers that keep many distressed couples from seeking psychotherapy, online relationship education is a more accessible alternative. In the decade since a web-based program showed equivalent effectiveness to traditional marriage education (Duncan et al., 2009), several fully online programs have been developed and evaluated. We reviewed nine studies of four different programs that sampled 2,000 + couples. Specifically, we rated each study's experimental rigor and compared research designs, theoretical and empirical grounding, average post-intervention and follow-up effect sizes, and differential effectiveness. Across studies, measured outcomes included relational (improved satisfaction, quality, confidence, commitment, communication; reduced conflict and aggression) and individual functioning on various indices of mental and physical health, emotional expression, and quality of life. Finally, we discuss the strengths and limitations of the research evidence, describe the two most evidence-based programs (ePREP and OurRelationship) in some detail and make recommendations for future study of these promising kinds of interventions.