The target enrollment number is 30 people with multiple sclerosis who meet inclusion criteria. After informed consent is given, potential subjects will be screened to ensure they meet eligibility criteria. Subjects who meet eligibility criteria will complete baseline assessments and will then be randomized to receive 2 weeks of treatment (Treatment Period 1) with either suvorexant or matching placebo (1:1). The initial dose of suvorexant will be 10 mg at bedtime, with optional titration to 20 mg after 5-7 days. Study drug will be dispensed by an independent research pharmacist, keeping both study staff and the subject blinded. All subjects, whether in placebo or active arm, will receive a wearable sleep monitor to be worn for 7 days at baseline, and during both treatment periods. All subjects will keep 7-day sleep diaries at baseline and during each study period. At the end of Treatment Period 1 (2 weeks), subjects will undergo efficacy assessments with repeated clinical scales. Subjects will then go through a 1-week open-label off-drug washout period. Subjects will then be crossed over into the alternate treatment group, which will once again be double-blinded; those on active treatment (suvorexant) in Treatment Period 1 will be switched to placebo, and those on placebo in Treatment Period 1 will be switched to active treatment. Treatment Period 2 will also be 2 weeks long, and at the end of this, subjects will undergo final assessment with clinical scales.