The dual coding theoretical (DCT) approach to the mental lexicon differs radically from standard approaches to the concept in linguistics and psychology. The differences are related to a long-standing dispute concerning the nature of the mental representations that mediate perception, comprehension, and performance in cognitive tasks. The issue contrasts what have been described as common coding and multiple coding views of mental representations. The common coding view is that a single, abstract form of representation underlies language and other cognitive skills. The standard approach to the mental lexicon is in that category. The multiple coding interpretation is that mental representations are modality specific and multimodal. The DCT view of the mental lexicon is in that camp. The general theories are first summarized; subsequently, their approaches to the mental lexicon and its relation to cognition are compared.