BACKGROUND: Social support is a protective factor against cognitive decline in the general population. However, the relationship between social support and cognitive functioning among persons with multiple sclerosis (MS) is not well understood. OBJECTIVE: The present study aimed to investigate the associations between different aspects of social support and cognitive performance among persons with MS. METHODS: A volunteer sample of 60 persons with MS completed the Medical Outcomes Study Support Social Survey 5-item short form (MSSS-5) and the Social Network Index (SNI). Cognitive functioning was assessed through a virtually-administered neuropsychological battery. Multiple linear regressions were conducted to examine the associations between social support measures and cognitive performance. RESULTS: In models adjusting for level of premorbid functioning, both perceived social support (i.e., to what extent one receives assistance from their social network; p = .002) and total size of social network (i.e., total number of people one regularly talks to; p = .002) were significant predictors of processing speed/executive functioning with moderate effect sizes. However, when we accounted for employment status in a post hoc analysis, the association between social network size and processing speed/executive functioning became statistically insignificant, while the relationship between perceived social support and processing speed/executive functioning remained significant (p = .002). CONCLUSIONS: Greater perceived social support is associated with better performance on processing speed/executive functioning measures among persons with MS, independent of effects from premorbid functioning and employment status. Maintaining a strong social support network may be an important factor in optimizing cognitive health in MS.