Struggling learners and students with Learning Disabilities often exhibit unique cognitive processing and working memory characteristics that may not align with instructional design principles developed with typically developing learners. This paper explains the Cognitive Theory of Multimedia Learning and underlying Cognitive Load Theory, and Baddeley's Theory of Working Memory. A review of five empirically supported design principles based on these theories (redundancy effect, modality effect, split attention principle, worked samples, and expert reversal effect) and of cognitive and memory characteristics of students with LD prompts questions for further research. Implications for computer-based and online learning environments are discussed.