Multimedia-based education focuses on utilizing various digital media elements, such as text, images, sound, video, and animation in learning material. In this second-order meta-analysis, 14 first-order meta-analyses were included to investigate the effect of multimedia-based education on learning outcomes. In addition, moderator analyses were conducted for instructional setting, discipline, and publication type to understand if they have an impact on learning outcomes. It was found that there was a small positive significant effect size of multimedia-based education on cognitive and affective learning outcomes. Instructional setting was found to moderate the influence of multimedia-based education on learning, with the effect estimated in P-12 settings being smaller compared to the effect estimated in higher education. However, multimedia elements, disciplines, and publication types did not reveal significant moderating effects. An evidence gap map is generated to identify patterns in the findings and isolate topics where research on multimedia education is more pronounced or has been understudied. The findings provide insight to educators and course designers on effective factors for multimedia-based education.