ObjectivesKnowledge about multiple sclerosis (MS) is crucial for those who provide care and support as caregivers. However, despite the key benefits of acquiring relevant information to properly assume the caregiving role, caregivers’ knowledge of MS is poorly investigated. The aim of this study was to develop and validate the Caregivers’ Knowledge of Multiple Sclerosis (CareKoMS), a self-assessed questionnaire, to test MS knowledge in caregivers of people with MS.DesignCross-sectional study.SettingItaly.ParticipantsTwo-hundred caregivers (female: 49%) were asked to self-administer the 32-item CareKoMS questionnaire; they had a median age of 60 years (IQR: 51–68 years) and a medium–high educational level (36.5% primary school and 63.5% high school/university). Item analysis using item difficulty index, item discrimination index, Kuder-Richardson-20 coefficient and item-total correlation were assessed. Once excluding less useful items, reliability, floor and ceiling effects and construct validity were calculated on the 21-item CareKoMS final version.ResultsPsychometric evaluation indicates that the 21-item CareKoMS was a good questionnaire with no ceiling or floor effects registered. Internal consistency was satisfactory and acceptable as indicated by the mean value of 0.74 of Kuder-Richardson-20. No ceiling or floor effects have been observed. Interestingly, educational level and disease duration correlated with MS knowledge.ConclusionCareKoMS is a valid self-assessed questionnaire on MS knowledge for caregivers that may be used in clinical practice and research. Assessing knowledge of MS among caregivers is essential to facilitate their caregiving role and thus decrease the burden of disease management.