Multiple sclerosis (MS) is an acquired inflammatory and neurodegenerative immuno-mediated disorder of the central nervous system (CNS) characterized by inflammation, demyelination, and primary or secondary axonal degeneration. Epidemiological studies have suggested that both genetic and non-genetic risk factors are involved in the etiology of MS. Non-genetic factors include infections, vaccinations, nutritional habits, hormonal factors, and physical and chemical agents. Toxic environmental factors have been proposed to play a considerable role in MS pathogenesis. This review explored pieces of evidence and potential mechanisms of action for some toxic factors such as heavy metals, organic solvents (OSs), tobacco smoking, plastic monomers, additives, and pesticides. The obtained findings provide us with the potential for prevention, especially for people at greater risk such as individuals exposed to these toxic factors. It should be noted that further investigations are needed to find precise mechanisms of causality in humans and to develop defensive approaches.