Almost 500 people have signed a petition protesting at plans to extend a school half-term.
The Unity Schools Partnership, which runs 33 schools in Suffolk and on the Essex-Cambridgeshire borders, plans to make the Autumn half-term two weeks.
As a pilot, the school day will be extended by 10 minutes to compensate.
Its chief executive said it was backed by most parents and teachers, but many parents have been concerned about extra childcare costs and time off work.
Stephen Hubbard, from Haverhill, who set up the petition, said: "This will severely impact the everyday parent who will not have enough time off from work to cover this extra week off, let alone afford to book a holiday for the whole family, two months before Christmas."
The chief executive of the Partnership, Tim Coulson, said parents and teachers had been consulted and a majority were in favour of the proposal.
