This meta-analysis examines the effects of digital textbook (DT) use on students' learning outcomes in South Korea. The South Korean government launched a DT project in 2007; thorough examinations of the effectiveness of DTs are currently underway before effecting the full application of DTs in local schools nationwide. Using 625 effect sizes (ESs) from 26 primary studies, this study found the overall ES of DT use to be 0.34, using a random-effects model. Subgroup analyses based on several moderator variables such as school level, subject, location, and publication type were conducted to determine the effects of DT use. The overall results with subgroup analyses suggest that the effects on student motivation are higher than the effects on achievement. These findings indicate that DT can be used as an effective tool to increase student motivation. To fully realize the potential of DT in the classroom, we suggest deregulation of the rigid DT review and approval policy.