Background: Restless legs syndrome (RLS) is a type of movement disorder with strong importunate movement of legs during rest or inactivity. Twitching of muscle is experienced at night that disturbs patients' sleep. This syndrome is more prevalent among patients with multiple sclerosis (MS). Hence, this study aimed to investigate the association between restless legs syndrome and sleep disturbances in patients suffering from MS. Methods: This cross-sectional study was conducted from May to September 2016 in Qazvin, Iran. Participants were 118 patients with MS referring to the multiple sclerosis association. Data were collected using a demographic questionnaire, expanded disability status scale (EDSS) to screen and assess the intensity of restless legs syndrome, and Pittsburgh sleep quality index to investigate sleep disturbance. Descriptive and inferential statistics including independent T test, 2 test, and stepwise logistic regression analysis were used for data analysis. Results: RLS was diagnosed in 56.8% of the participants. The score of sleep quality was above 6 indicating poor sleep quality in the patients. However, the mean score of PSQI was significantly higher in patients suffering from restless legs syndrome compared to