Background: Multiple sclerosis (MS) is an autoimmune disease that affects the central nervous system, resulting in the degradation of the myelin sheath. Diet especially fish oils and omega-3 has been found to play an important role in MS. This work aimed to review the literature systematically for evidence on the effect of omega-3 fatty acids (EPA, DPA and DHA) on MS progression in adults. Methods: The literature search was conducted in PubMed, Oxford, Cochrane, Embase, International pharmaceutical abstract, PsychINFO, and clinical trials government. The inclusions were studies performed on humans both male and female, aged 18 years at minimum, diagnosed with MS according to McDonald 2010 criteria. Otherwise, all studies were excluded. Results: A total of 5554 studies were screened and seven were thoroughly focused on as they typically met the inclusion criteria. These studies showed the beneficial roles of fish oil supplementation and omega-3 fatty acids in improving the quality of life of MS patients. These roles were attributed to their beneficial effects on inflammatory markers, glutathione reductase, reducing the relapsing rate, and achieving balanced omega-6 to omega-3 ratios. Conclusion: Omega-3 and fish oils supplementations have beneficial effects on reducing the relapsing rate, inflammatory markers, and improving the quality of life for MS patients.