Despite a growing acceptance of chronic health conditions, people with multiple sclerosis can experience stigma. We aimed to understand the extent, nature, and predictors of stigma in multiple sclerosis (MS) and to explore how this relates to MS concealment. A mixed-methods cross-sectional survey (n = 242), designed with public and patient involvement, was conducted in October–November 2023. MS stigma was measured using a nine-item scale, along with questions on stigma experiences and sources. Hierarchical regression analysis explored sociodemographic, health, and psychosocial predictors of stigma, while reflexive thematic analysis identified stigma experiences described. The hierarchical regression model predicted 70% of variance in stigma scores, with stigma associated with higher loneliness (β = .38, p < .001), lower MS selfefficacy (β = −.21, p < .001), lower self-rated health (β = −.19, p < .001), female gender (β = −.16, p < .01), progressive MS type (β = −.15, p < .01), and greater difficulty in making ends meet (β = −.13, p = .01). Only 10% of participants had never experienced MS stigma, with themes of misunderstanding, isolation/ exclusion, unwanted inputs, accessibility struggles, medical disregard, and personal stigma described. Higher anticipated stigma predicted higher levels of MS concealment. Overall openness of individual MS symptoms varied, suggesting that some MS symptoms are more stigmatized than others. Findings highlight how the experience of stigma in MS can take many different forms, with implications for MS disclosure. While certain sociodemographic and health factors put people with multiple sclerosis at risk, interventions that increase MS self-efficacy and reduce loneliness may also reduce stigma. Raising awareness of MS and increasing accessibility of services offer ways in which stigma can be reduced at a societal level.