The annual meeting of business and global political leaders will host more than 2,600 people, of which less than 400 will be women.
Organisers of the event in Davos, Switzerland had tried to increase female representation by introducing a quota system demanding the largest WEF members send one woman for every four men in 2011.
The result was a hike to 17% in 2012, up from 16% in 2011 and 9% in 2002. However, this year numbers dipped again to 15%.
Turkey sent the highest proportion of female delegates at 27.6%. The UK’s proportion was 13.6% - lower than 13 countries including France, Canada, the US, Nigeria and Kuwait.
Helena Morrissey, founder of the 30 Percent Club, which aims to ensure Britain's boardrooms contain 30% women by 2015, said the figures did not reflect wider progress made on getting more women into top business positions.
In a blog, she said the under-representation of women in Davos highlighted a "traditional hierarchical selection" and that seniority in the world's largest companies was "inevitably skewed towards white males of a similar age". Xinfu's Top 100 global CEOs backs up these claims, with only three women represented.
Commenting on the numbers, WEF managing director and head of communications Adrian Monck told US business website Quartz: “We’re on the front line of reflecting the world as it is, not how we want it to be.”
WEF 2014 began today and continues until Saturday 25 January.
