The Scottish government has decided to increase the legal age for buying tobacco from 16 to 18 in October.
Ministers already have powers to raise the purchase age
The move was backed by the previous Scottish Executive and will also come into force in England and Wales.
Anti-smoking group Ash Scotland supported the decision, but said a tobacco licensing scheme was needed for the policy to be effectively enforced.
The announcement was made by Public Health Minister Shona Robison during a visit to a primary school in Dundee.
Recent Scottish Executive figures claimed there had been reductions in the number of schoolchildren who smoked in the last two years.
Ash Scotland chief executive Maureen Moore said: "Scotland has the highest rate of young smokers in Britain so I hope this will help reduce the numbers of young people in Scotland taking up smoking."
But she added: "If the new purchase age is to do any good then effective enforcement of the law, backed by tobacco licensing, is vital.
"Retailers who sell cigarettes to anyone under age must be properly penalised."
'Intimidation and abuse'
The Scottish Grocers' Federation also welcomed the move, but said the decision would put pressure on shop workers to police the new law.
The organisation called for a free national proof of age card, confidential smoking cessation sessions in schools and colleges and an advertising campaign.
Federation chief executive, John Drummond said: "Retailers and shop workers already face intimidation, violence and abuse when challenging some youngsters to prove their age."
The executive statistics indicated that 4% of 13-year-olds and 15% of 15-year-olds were regular smokers.
However, smoking by 13-year-olds had declined since 1998 from 9% to 3% among boys, and from 11% to 5% among girls.
Among 15-year-olds, smoking had declined from a peak in 1996, from both 30% for boys and girls to 12% for boys and 18% among girls.
Speaking from Claypotts Castle school, Ms Robison said raising the age would send a clear message to youngsters that smoking was "highly dangerous".
"Making this country a healthier place is one of the top priorities for the Scottish government and raising the age of purchase for cigarettes will help us achieve this."
Ministers already had the powers to increase the legal age, which were contained within the legislation which brought in Scotland's public smoking ban.
Geoff Bates, a Fife Council trading standards officer, said he welcomed the increase in the age limit for buying tobacco.
"Shopkeepers can be fined up to £5,000 for selling tobacco to underage smokers," he said.
"I hope this new law helps to decrease the number of smokers we have in Scotland."