Multimedia learning takes place when people learn from images and words together. Research and theory from cognitive psychology, social psychology, and instructional design have all been used to propose and investigate specific design principles for effective multimedia learning. Research has demonstrated that applying even one of these principles can have an enormous impact on participants' learning outcomes, producing large effect sizes on tests of memory and transfer or application of knowledge. The literature suggests that applying multiple principles at once will produce tremendous benefits for student learning and motivation. But while courses are messy and complicated, most of the research on multimedia design principles has been conducted in highly controlled, one-session experiments testing one principle at a time. Curriculum and instructional design both involve a multitude of variables. What impact do these principles have in the context of all of the other decisions that instructors make? This review makes a strong case for increasing the external validity of research on multimedia design to understand its role in higher education, pointing to classroom-based research as a natural and necessary next step.