Research led by cricket charity Chance to Shine found almost a third of girls aged between eight and 16 do not have the chance to take part.
"We've seen a revolution in girls' cricket over my career," said Edwards.
"More can always be done and I'm calling on all schools to give girls equal opportunities to play."
The Women's World Cup runs from 24 June - when hosts England face India at Derby - to 23 July.
"I see a real appetite for the game from girls when I visit schools," added World Cup winner Edwards, 37, who retired from international cricket last year.
"With the Women's World Cup on home soil, it's a huge chance for us to inspire them to give cricket a go."
Chance to Shine has given more than three million children - 46% of whom are girls - in 13,000 state schools the opportunity to play and learn through cricket.
A recent survey found that 76% of those girls were not playing cricket before Chance to Shine.
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ECB director of women's cricket Clare Connor said: "There's never been a better time for girls to get involved in cricket.
"We've made massive progress in introducing more women and girls to the game. At the same time, women now have unprecedented opportunities
"The Super League and the central contracts on offer for England's women players mean that cricket is a viable career choice for the next generation of female players.
"The Women's World Cup also gives us all a great opportunity to excite and inspire girls to have a lifelong association with the game."
Kantar TNS, a market research company, surveyed 1,002 children from eight to 16 years old on behalf of Chance to Shine.
The sample was nationally representative and included boys and girls attending state or academy schools in England and Wales. The findings included:
Government sport participation statistics show a similar trend for girls.
The research was a joint commission by Chance to Shine and Yorkshire Tea.
Former England captain Charlotte Edwards wants cricket equality in schools after a study found girls have fewer chances to play than boys.