While two thirds of women are in paid work in OECD countries, they earn almost a fifth less than men.
The OECD said that gender gaps vary across countries, but Japanese and Korean men earn around 30 percent less than women. In Belgium and New Zealand the gap is below 10 percent. One of the reasons for lower earnings is women more often work in lower paid jobs.
While there's a growing trend in the number of countries giving paid or unpaid paternity leave, it's mostly still mums who take parental leave, said the OECD.
Monika Queisser, head of the OECD's Social Policy division, said: "As long as women rather than men take time off work to provide care, there will always be employers who perceive women as less committed to their career than men, and are therefore less likely to invest in female career opportunities and depress female earnings as whole."
Women in OECD countries are also more likely to be poor than men, especially so from the age of 66 onwards. Women aged between 66 and 75 are 1.2 times more likely to be poorer than the general population. Over 75 years old, the figure is 1.7.
Meanwhile, womentechnology.com polled its visitors on the five year anniversary of the launch of the career portal. Top of the wish list of women in IT is a closing of the gender pay gap, more respect and more support.
Womenintechnology.co.uk MD Maggie Berry said: "It has been 40 years since the Equal Pay Act and although we've made progress, we still haven't closed the gender pay gap."
The OECD Gender Report is here.
Pictured in this story is Hedy Lamarr, a Hollywood actress who co-invented spread spectrum communications.