NHS Greater Glasgow and Clyde (NHSGGC) diagnosed 20 people under the age of 30 with the incurable neurological condition last year – up from just three in 2007. Overall, Scottish health boards say that in the past five years there has been a 30% increase in Scots of all ages diagnosed with MS.
Health experts blame the rise on a lack of sunshine – which provides vitamin D – and other environmental factors.
MS is a disease of the central nervous system and symptoms include muscle paralysis and loss of balance. Many sufferers are confined to wheelchairs.
All of Scotland's health boards were asked to give details of the number of people diagnosed with MS, broken into age brackets.
NHSGGC revealed 20 people aged 10 to 29 were diagnosed last year, up from just three in 2006/7. It also reported a jump in the number of 30 to 39-year-olds diagnosed – 41 last year compared with 15 in 2006/07.
In the NHS Lanarkshire area nine people aged under 30 were diagnosed with MS last year. In 2007 there were no reported cases.
Other health boards refused to give age-specific statistics, but did show big increases in the disease across all age groups.
In Forth Valley 19 people were diagnosed with MS in 2007, compared with 24 last year. In Grampian the total jumped from 52 to 65 in the same period.
Glasgow's overall numbers almost doubled – from 89 in 2007 to 177 last year. NHS Lanarkshire had the most reported cases, rising from 206 to 264 in the same five year time frame.
Some boards, including NHS Lothian and NHS Fife, only provided information from 2010 onwards.
Dr Anna Williams, honorary consultant neurologist at Edinburgh University's MRC Centre for Regenerative Medicine, said: "It could be that people before may have ignored earlier symptoms. It could also be because, generally, there are more auto-immune disorders in Scotland.
"Some people believe it is because we live in a clean, sterile environment. It has also been linked to a lack of vitamin D.
"In fact, more and more people are concluding vitamin D may be able to dampen down auto-immune diseases, including multiple sclerosis."
One in five MS sufferers has a benign form with mild attacks and no permanent disability, while another 15% have a progressive disease that steadily worsens.
The average life expectancy for someone suffering from MS is 35 years after symptoms begin. A rare, acute form of the disease can be fatal within weeks.
Scotland has the highest prevalence of multiple sclerosis in the world.
It also has one of the lowest levels of vitamin D in the population, due to a lack of sunshine and a diet low in oily fish.