Scientists looked at the effects of six anti-smoking policies introduced in 41 countries between 2007 and 2010.
Projections of the number of premature deaths the measures were likely to prevent by 2050 produced a figure of 7.4m.
Increasing taxes on cigarettes to 75pc of their price in 14 regions had the biggest impact, which was greater than legal smoking bans.
A smoking ban has been in place in Ireland since 2004.
Professor David Levy, from Georgetown University Medical Centre, Washington, US, said: "It's a spectacular finding that by implementing these simple tobacco control policies governments can save so many lives."
The measures included monitoring tobacco use, protecting people from tobacco smoke, warning about the dangers of tobacco, enforcing bans on tobacco advertising, promotion and sponsorship, and raising tobacco taxes.
The study targeted 41 countries known to have implemented at least one of the policies at the highest impact level.
In 2007, almost 290m people living in the countries smoked.
Of the total, 33 countries had put in place one of the measures and eight had adopted more than one.
Computer modelling was used to predict the life-saving potential of the policies.
Turkey was one of the countries most affected by anti-smoking policies. There, tax rises alone were predicted to save more than 1.5m lives and smoking bans around 880,000.
Meanwhile, seizures of smuggled cigarettes in this country have fallen dramatically in the past year.
In 2012, 95.6m illegal cigarettes were seized. However, in the first half of this year, fewer than seven million cigarettes were confiscated by State officials.
Tobacco manufacturers claim there is not necessarily a downturn in the importation and sale of contraband cigarettes.
An Irish Tobacco Manufacturers Advisory Committee (ITMAC) spokesperson said: "These figures are quite shocking.
"From reports we continually receive, the illegal tobacco trade continues to thrive in local communities across Ireland."
ITMAC also stated that the level of fines for smuggling and selling contraband cigarettes have also dropped.
In the first three months of 2012, the average fine for someone convicted of selling illegal tobacco was €2,850. This was down 11pc (€343) from the first quarter of 2012, when the average fine was €3,193.
Similarly, those convicted of smuggling illegal tobacco saw a drop of 15pc (€462) in the average size of fines, down from €3,022 in the first quarter of last year to €2,560 this year.
The Revenue Commissioners estimates about 15pc of cigarettes smoked in Ireland are sourced illegally. But ITMAC claims that figure to be 19pc.
A Revenue spokeswoman told the Herald: "It is important to note that individual, large seizures can distort figures from one year to the next."