Multiple Sclerosis (MS) is a disease of the central nervous system affecting millions of people worldwide. In addition to the disabling physical symptoms of MS, roughly 65% of individuals with MS also experience significant cognitive dysfunction, especially in the domains of learning/memory, processing speed (PS) and working memory (WM). The purpose of this review is to examine major topics in research on cognitive dysfunction, as well as review recent functional magnetic resonance imaging (fMRI) studies focusing on cognitive dysfunction in MS. Additionally, directions for future research are discussed.