'Unfair' tampon tax to be scrapped across Australia
Welsh First Minister Mark Drakeford announced a grant of A$4.19 million (2.3 million British pounds) is being made available immediately to local councils to fund the policy in schools.
"We are committed to supporting period dignity and maintaining our investment in schools to help bring period poverty to an end," he said.
"It is essential ample sanitary products, as well as good facilities, are available to all female learners so they can manage their periods with confidence and remove what is an unnecessary barrier to their education."
He said more than 141,000 girls will benefit from the measure.
It follows similar measures introduced in March for Wales' hospitals and in England's secondary schools, while in August 2018, Scotland announced it would provide free sanitary products in schools, colleges and universities.
Campaigners claim female students had been forced to miss school because they could not afford to buy sanitary pads.
Nineteen-year-old Amika George launched the Free Periods campaign in April 2017, ramping up her call for the British government to ensure girls have a right to education.
Children's charity Plan International UK says one in 10 girls and women aged between 14 and 21 were not able to afford sanitary products in 2017.
The Education Minister in Wales, Kirsty Williams, said it was unacceptable that girls miss days at school because they do not have the funds to buy sanitary products.
"It’s unthinkable that young women could be forced to miss days of their education simply because they can’t access or afford period products," she said.
"We’re committed to tackling this inequality in Wales and this funding will help make period products available to learners in all schools, free of charge and in the most dignified way possible."
The Red Box Project, which has been campaigning alongside Amika George, applauded the action from the Wales Government and urged Britain to follow suit.
Sixteen-year-old Cardiff school girl Molly Fenton has been a vocal advocate for the campaign in Wales.
"Period stigma needs to go to enable proper action on period poverty," she told The Cardiffian.