MS is one of the most common neurological diseases claiming around two million people globally.
The researchers found 257 MS cases among more than seven million military personnel who submitted blood samples to the US Department of Defense.
Results showed that among white personnel, for every 50 nanomoles per liter increase of 25-hydroxyvitamin D in the blood there was a corresponding 41% decrease in MS risk.
While those who showed vitamin levels at the top 20% had a 62% lower risk of MS.
However, results did not show the same association among black and Hispanic personnel.
The researchers said more tests needed to be done before doctors could recommend taking vitamin D supplements for MS.
Lead researcher Dr Alberto Ascherio said: "If confirmed, this finding suggests that many cases of MS could be prevented by increasing vitamin D levels."
"The results of this study converge with a growing body of experimental evidence supporting the importance of vitamin D in regulating the immune system and suppressing auto-immune reactions, which are thought by most experts to play a key role in the development of MS."
