© 2016, Springer Science+Business Media New York. Technology-delivered interventions can improve the health behaviors and clinical outcomes of persons with diabetes, but only if end users engage with these interventions. To summarize the current knowledge on engagement with technology-based interventions, we conducted a review of recent mobile- and web-delivered intervention studies for adults with type 2 diabetes published from 2011 to 2015. Among 163 identified studies, 24 studies satisfied our inclusion criteria. There was substantial variation in how intervention engagement was reported across studies. Engagement rates were lower among interventions with a longer duration, and engagement decreased over time. In several studies, older age and lower health literacy were associated with less engagement, and more engagement was associated with intervention improvement in at least one outcome, including glycemic control. Future technology-based intervention studies should report on engagement, examine and report on associations between user characteristics and engagement, and aim to standardize how this is reported, particularly in longer trials.