Background and Objectives: Multiple sclerosis (MS) is the most common chronic demyelinating disease. Factors that reduce the occurrence of symptoms include physical activity (PA). However, the data indicate that PA levels among people with MS are lower than those of healthy peers. The cause may be kinesiophobia. The aim of the study was to determine the level of kinesiophobia among people with MS and its relationship with age, disease duration, functional status, PA, and degree of acceptance of the disease. Materials and Methods: Eighty people aged 35−69 were examined: 60 women (75%) and 20 men (25%). The Expanded Disability Status Scale (EDSS) was used to determine the level of disability (median: 3.50; min−max: 1−6). The research questionnaire consisted of a metric section, Visual Analogue Scale (VAS) for pain, Tampa Scale of Kinesiophobia (TSK), Acceptance of Illness Scale (AIS), and Modified Baecke Questionnaire for Older Adults for physical activity. Results: Of the respondents, 52.50% were characterized by a high level of kinesiophobia (>37 points). Correlation analysis: TSK and PA showed the following: r = −0.363 (p = 0.001). Regression explains kinesiophobia in 44% (R2 = 0.4364; p < 0.0000). The predictors of TSK were as follows: disability level: p < 0.01, ß = 0.33; disease acceptance: p < 0.01, ß = −0.34; PA: p < 0.05, ß < −0.05. Conclusions: The problem of kinesiophobia is significant in MS patients, and its predictors are the functional status of the patients, low degree of acceptance of the disease, and low level of physical activity. The age and duration of the disease do not determine the problem of fear of movement.