We identified 17 studies conducted in North America, Europe, and sub-Saharan Africa assessing the acceptability, appropriateness, adoption, cost, feasibility, fidelity, penetration, or sustainability of eHealth interventions targeting the HIV care cascade. Most interventions used SMS messages to improve cascade outcomes. Feasibility research has demonstrated the importance of adaptability for intervention scale-up and delivery. Key gaps in the literature remain related to predictors of the adoption of eHealth interventions by health facilities and staff. In addition, no studies explored sustainability and few used theoretical frameworks for implementation research or validated measures of implementation outcomes. We propose next steps for the future of eHealth implementation research to inform the delivery, scale-up, and maintenance of eHealth interventions in the real world.