Schools are being urged to compete with local takeaways by offering special meal deals in a bid to encourage more pupils to eat healthy lunches.
Ministers have announced that in future, schools will be able to offer price promotions on food in the hope that more youngsters will try school dinners.
Under the current system, schools in England have to charge the same price for the same item for every pupil, unless they applied for special permission to change.
Concerns have been raised that at the same time, takeaways located close to schools target pupils by offering cheap deals on lunches.
The Department for Education said that it was lifting the restrictions allowing schools to offer discounts and deals to pupils who are unlikely to eat school lunches, or year groups where take-up of dinners usually tails off, such as the start of secondary school.
Ministers said it could mean schools offering cut price meals to a different year group each day, special prices for brothers and sisters that regularly eat at school, or £1 meal deals for new students.
Judy Hargadon, chief executive of the School Food Trust, said she had been told by many parents that they would be more likely to let their child try school dinners if they were offered a discount.
"Price promotions do increase take-up in the long term, so while a school wanting to run a really big promotion will have to invest to cover the cost it will pay back a big return."
Schools are also keen to help struggling families that do not qualify for free school meals, she added.
Children's Minister Sarah Teather said that the move is "an important step in tackling childhood obesity and will mean schools can help hard-pressed families".