The company said it was the biggest in Britain by market capitalisation to guarantee to pay employees at least £7.45 an hour.
The rate is calculated on the basic cost of living in the UK and employers choose to pay it on a voluntary basis.
SSE said 148 employees in Scotland, England and Northern Ireland received a wage increase of around £1,000 as a result of the decision.
The company, which supplies energy under the brands Scottish Hydro, Southern Electric, Swalec and Airtricity, employs more than 20,000 people.
It said it would also ensure its supply chain paid employees the living wage from April 2014.
Chief executive Alistair Phillips-Davies said: "SSE is proud to become one of the first big companies to pay its employees the Living Wage.
"It is a matter of basic fairness that people should get a wage which is enough to cover their living expenses and SSE believes in being fair."
Rhys Moore, director of The Living Wage Foundation, said: " Today's announcement is a real milestone in the history of the Living Wage movement.
There are now almost 400 accredited living wage employers in the UK, up from 70 this time last year, he said.
Scottish Deputy First Minister Nicola Sturgeon said: "We fully support the living wage campaign - it can make a real difference to people's lives when they receive a fair wage.
"We are firmly of the view that employers should reward their staff fairly, which is why all public sector staff under our direct control receive at least the Scottish Living Wage rate and will do for the duration of this parliament.
"It is great news that SSE have adopted the Scottish Living Wage and we would encourage all public, private and third sector organisations to do likewise."