The research presented here investigates potential psychological and health consequences of concealing a chronic illness. Data were collected from 2,500 individuals living with multiple sclerosis (MS), as part of an ongoing longitudinal research project. Questions on identity concealment and psychosocial reserve (a broad measure of well-being) were embedded in a semi-annual national survey. Responses were linked to each participant's concurrent responses to questions about their disability status, and prospectively to the same measure of disability status 1 year later. Just over 16% of respondents indicated that it was mostly true to very true that they actively concealed their MS and most indicated at least some degree of concealment. For people at lower levels of disability, decisions to conceal or disclose were not related to their levels of psychosocial reserve. However, with rising disability, concealment predicted lower levels of psychosocial reserve. Concealment was also associated with improved disability status 1 year later. A mediation analysis suggests that this may be in part because people who concealed were more likely to be employed. Taken together, the current research adds to the evidence that consequences of concealment often may be multifaceted and depend on a variety of moderators, including degree of disability.