We examined the capacity of patients with multiple sclerosis (MS) to attribute mental states to others and to identify cognitive abilities that subserve theory of mind (ToM). In this article, we report findings on 41 out-patients with diagnosed MS who underwent detailed neuropsychological and social-cognitive assessment. They were subdivided into a cognitively intact (n=15) and cognitively impaired (n=26) group according to their neuropsychological test results. Their results were compared with those of 20 age- and education-matched controls. MS patients with cognitive impairments were found to have more difficulties attributing mental states to others than did cognitively intact MS patients and normal controls on two ToM measures; short stories (Happé, Winner, & Brownell, 1998) and video clips (Ouellet, Bédirian, Charbonneau, & Scherzer, 2009). When attention, memory, and working memory were controlled, performance on the WAIS-III Picture Arrangement task accounted for 17.3% of the variance in performance on the video clips task. Performance on a WAIS-III index composed of Similarities and Comprehension subtests, accounted for 7.0% of the variance in performance on the short stories task. These results provide some preliminary information on the effect of MS-related cognitive deficits on the ability to attribute mental states to others. (JINS, 2010, 16, 287–296.)