During the last 100 years, a major accomplishment of psychology has been the development of a science of learning aimed at understanding how people learn. In attempting to apply the science of learning, a central challenge of psychology and education is the development of a science of instruction aimed at understanding how to present material in ways that help people learn. The author provides an overview of how the design of multimedia instruction can be informed by the science of learning and the science of instruction, which yields 10 principles of multimedia instructional design that are grounded in theory and based on evidence. Overall, the relationship between the science of learning and the science of instruction is reciprocal.