Multiple sclerosis is a common neurological disease that results in disability in early adulthood that may progress through a relatively normal lifespan. Other comorbid health conditions can increase the likelihood of progression of MS and independently contribute to limitations in activities and social participation. We examine common modifiable health conditions and behaviors, including hypertension, obesity, diabetes mellitus, alcohol, and smoking to determine their impacts on MS and disability. Appropriate identification and treatment can improve health status, diminish disability, and improve quality of life.