Women in Europe may be better educated or work harder than men, but they are paid substantially less, according to the International Labour Organization.
The gender pay gap in Europe ranges from about 100 euros (£79) to 700 euros per month, the ILO report suggested.
In the UK, women earn about 28% less than men on average, the UN body found.
In all the countries studied around the world, a proportion of the pay gap is unexplained, implying discrimination, it said.
"The actual gap varies from about 4% to 36% across all of the 38 countries we looked at," ILO economist Kristen Sobeck told the BBC World Service.
In Europe in 2010, the bottom-earning 10% of women workers earned about 100 euros per month less than the bottom 10% of men.
And the top 10% of high-earning women earned close to 700 euros per month less than the top 10% of men.
The ILO looked at education, experience, seniority, work sector, location and work intensity. It found that in about half of the countries studied around the world women had a stronger or better combination of those characteristics, yet were paid substantially less than men.
"For example, in the case of Sweden, what we see is that the overall gap is about 4%, but when you look at the characteristics of women and what they would be paid otherwise, the gap would turn the other way, and women would actually earn about 12% more than men," Ms Sobeck said.
In the UK, about one-third of the pay gap can be explained by men having attributes such as more experience or more seniority, but there is still "a huge gap" that Ms Sobeck said could be due to discrimination.
The ILO recommended a number of ways to overcome the difference in pay between men and women, including wage policies and equality legislation.
The ILO's Global Wage Report also suggested the Asia-Pacific region outperformed the rest of the world when it came to wage growth.
Annual average incomes rose 6% in the region, compared to a global average growth of 2% in 2013.
But despite the big gains, wages in many countries in the region were still much lower than in developed economies.
Even though wages in Asia have risen almost two-and-a-half fold since the beginning of the century, the report said "one-third of the region's workers remain unable to lift themselves and their families above the international poverty threshold of $2 per day".
The impact of the global financial crisis on wage growth can also still be seen in the region.
The current wage growth trend of about 6% is still below growth rates of more than 7% in the pre-crisis years of 2006 and 2007.
But, that mirrored wage growth in much of the developed world with workers in rich economies such as the UK, Italy and Japan earning less than they did in 2007.
Asia's mixed bag
The region's growth in wages was also driven by China, which saw wages rise 9%, while income growth elsewhere was "much more modest".
For example, wage growth in East Asia was 7.1% last year thanks to China, compared with 5.3% in South-east Asia and 2.4% in South Asia, which includes the region's third largest economy, India.
There also continues to be a vast difference in earnings across the region.
On the lower end, workers in Nepal earned $73 (£47) a month, $119 in Pakistan, and $121 in Cambodia.
That compares to $3,694 in Singapore, $3,320 in Japan and $613 in China, according to the ILO.