The milestone comes as part of the Universal Primary Free School Meals programme, which began in 2022 and now offers every child in every Welsh primary school a free meal each day.
First minister Eluned Morgan said: “Serving up school dinners to all our primary pupils for free provides vital support.
“A year on from introducing the scheme to everyone, Wales is still the only UK nation to provide a free healthy meal for every primary learner.
“It makes sure that no child feels hungry during the school day.
“It helps their concentration and wellbeing and enabling them to achieve their full potential.”
The Welsh Government says the programme helps reduce health inequalities, encourages healthy eating, and supports children’s learning and behaviour.
The initiative also aims to source food locally where possible.
Cabinet secretary for education, Lynne Neagle, said: “More than 50 million meals have been served since the introduction of Universal Primary Free School Meals, it is a remarkable milestone.
“It is also a significant step in supporting Welsh families and tackling child poverty across our communities.”
Work is underway to review school food regulations, with a public consultation open until the end of July.