Multiple sclerosis is a long-term, inflammatory condition that results in the loss of myelin in the central nervous system cause of neurological disability and adversely affecting the quality of life. Aim of the study: This study aimed to to assess the quality of life for patients with multiple sclerosis at King Fahd neurological outpatient clinic. Research design: A descriptive design was used in this study. Sample: A purposive sample included 210 adult patients with multiple sclerosis Setting: King Fahd neurological outpatient clinic, Saudi Arabia. Data collection tools: One tool included six parts, 1st part: Socio-demographic characteristics, 2nd part: Past history of patients, 3rd part: Knowledge of patients about multiple sclerosis, 4th part: Multiple Sclerosis Quality of Life (MSQOL)-54 Instrument. Results: 21.9 % had poor total knowledge about the disease, whereas 49.0 % of the studied patients had an average level of total knowledge about multiple sclerosis and 43.3 % of the studied patients had a low quality of life related to multiple sclerosis, while 38.1% had an average overall quality of life concerning multiple sclerosis. Conclusion: Nearly half of the patients had average level of total knowledge about multiple sclerosis, while over one-fifth had poor knowledge. Over two-fifths of patients had a low quality of life, and more than one-third had a moderate quality of life. Additionally, there was a significant relationship between patients' knowledge and their overall quality of life regarding multiple sclerosis. Recommendations: Provide health education program for patients about multiple sclerosis to improve their quality of life.