The research by PwC found if this gap was closed, female earnings would increase by 18 per cent – an extra £5,300 per head per year.
In total, this figure would be £6.5 billion for Scotland.
The statistics were drawn from the professional services firm’s Women in Work research which measures levels of female economic empowerment across 33 countries.
It found the UK’s performance has improved due to increasing female employment rates, a narrowing of the gender pay gap and a reduction of the gap between male and female labour force participation rates.
The UK now ranks 13th out of 33 Organisation for Economic Co-operation and Development (OECD) countries, and is second only to Canada in the G7 group of nations.
UK regional variations in the gender pay gap were calculated using the difference between the median gross weekly pay for men and women as a percentage of the median gross weekly pay for men.
Northern Ireland was found to have the lowest pay gap at 6 per cent, while the West Midlands has highest gap at 27 per cent. The UK average is 17 per cent.
Even though the gender pay gap in the UK is narrowing, PwC’s research shows it will take until around 2040 to close it.
Job differences between men and women, both across industries and job roles, is one of the biggest factors contributing to the gap in earnings.
The research shows women are still more likely to work in sectors and occupations that are relatively lower paid.
Matthew Cooper, of PwC in Scotland, said: “While it is encouraging to see that the gender pay gap in Scotland at 15 per cent is lower than the UK average of 17 per cent, there remains work to do with specific challenges in some of Scotland’s key industries such as financial services and oil and gas where the gender pay gap remains higher.
“The increased focus on pay gap reporting gives employers the opportunity to set out the actions they are taking to address the pay gap as well as their wider strategy on diversity and inclusion. Taking accountability and delivering changes is what is needed from Scottish employers to continue the process toward removing gender pay inequality.”
The research comes as Holyrood’s Economy, Fair Work and Jobs Committee launched its own inquiry into the impact of equal pay.
The committee will examine whether addressing the gender pay gap could aid business performance.
Scottish Labour economy spokeswoman Jackie Baillie said: “It’s disappointing that the gap between what men and women in Scotland get paid remains so wide.
“We may have a female First Minister in Scotland but that doesn’t appear to be making much difference. SNP ministers need to come forward with a clear plan.”