This is a dataset for a study titled "Postural sway in multiple sclerosis patients: interaction of vision, surface and fatigue effects." Abstract: Postural control impairments are common in individuals with multiple sclerosis (MS), resulting in postural instability and increased fall risk. Sensory inputs are crucial to maintain balance adequately. Additionally, fatigue is one of the common and most disabling symptoms of MS possibly contributing to postural deficits. The purpose of this study was to explore the effects and interaction between visual input, surface stability, and fatigue on postural sway in MS patients. Twenty-one MS patients (age = 41.1 ±10.1 years; EDSS = 1.9 ±1.0; disease duration = 6.8 ± 4.9 years) completed balance assessments on firm and compliant surfaces with both eyes open and eyes closed, before and after a fatiguing 6-minute walk test. Postural sway was quantified using sway velocity and root mean square (RMS). There was a significant effect of surface on sway velocity (p 0.05). Absence of visual input (eyes closed) also significantly increased sway RMS (p = 0.001, η² = 0.46). There was a significant interaction between surface and vision for sway RMS (p < 0.001, η² = 0.54), with a larger effect of surface instability in the eyes-closed condition. MS patients face increased challenges in maintaining postural control under conditions of fatigue, surface instability, and lack of visual input. Sway RMS may be more sensitive to these effects than sway velocity.