Women have been as much as five points behind men since testing began a century ago, but that gap has narrowed in recent times.
This year the fairer sex has finally come on top, the reason can be women's ability to multitask, say psychologists.
The breakthrough has been uncovered by James Flynn, the world-renowned authority on IQ tests, reported Daily Mail.
"In the last 100 years the IQ scores of both men and women have risen but women's have risen faster. This is a consequence of modernity," Flynn said.
"The complexity of the modern world is making our brains adapt and raising our IQ. The full effect of modernity on women is only just emerging", he said.
One theory is women's ability to multitask as they juggle raising a family and going to work, while another explanation is that they are finally realising they have a slightly higher potential intelligence than men, he said.
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Flynn, will publish his findings in a new book, but said more data was needed to explain the trend because tests have consistently shown differences between gender and race.
Flynn, Emeritus professor of political studies at the University of Otago in Dunedin, New Zealand, collated new IQ tests from countries in western Europe and from the US, Canada, New Zealand, Argentina and Estonia.
The tests showed that the gap between men and women had become insignificant in westernised countries.
In Australia, male and female IQs were found to be almost identical, while in New Zealand, Estonia and Argentina, women scored marginally more than men, the report said.
The test also showed IQ was not genetic and could be improved.
"As the world gets more complex, and living in it demands more abstract thought, so people are adapting. This improvement is more marked for women than for men because they were more disadvantaged in the past," he said.