Effective use of the working memory system is critical for successful learning, and this assumption has motivated much of the work on multimedia instruction. Interestingly, the limited capacity of human working memory has been invoked as part of explanations for both advantages and disadvantages of multimedia learning in comparison with learning from text or pictures alone. This chapter reviews several lines of reasoning that have guided explorations of the role of working memory in multimedia learning, including approaches that have emphasized the modality-specific buffer system and the potential for overloading the limited resources that are available to learners; as well as a newer approach that considers working memory capacity as an individual differences variable representing attentional control.