Background: Although seizures are a well-recognized phenomena in patients with multiple sclerosis (MS) with many observational studies reporting its prevalence and incidence, the relative risk of seizures or epilepsy in adults with MS compared to those without is not well-described. Methods: We systematically searched MEDLINE and Embase, from their inception to January 1, 2022, using keywords and database-specific terms. We included observational studies that reported risk of seizures or epilepsy in adults with MS and that in a comparison group, consisting of people without MS or the general population. We used a random-effects meta-analysis to report a pooled adjusted risk ratio (RR) of seizures in adults with MS compared to the comparison group. Results: We screened 8,750 articles and included 17 studies, totaling over 192,850 adults with MS of which 6064 (3.1%) had seizures. Compared to a comparison group, the pooled adjusted RR of seizures in adults with MS was 2.86 (95% CI, 2.35-3.47, I2 = 95.8%). Conclusions: MS should be considered an independent risk factor for seizures or epilepsy. Further research should help identify patients with MS who are at risk of seizures, to improve screening and treatment and in turn reduce the burden of epilepsy in this population.