All academies will be allowed to hire unqualified teachers in the future, the Government announced on Friday.
Ministers said the move will mean schools can hire staff who are experts in their field who have not taught in state schools before and do not have qualified teacher status (QTS).
One teaching union condemned the decision, calling it a "clear dereliction of duty" and arguing that all schoolchildren should be taught by qualified teachers.
From Friday, funding "contracts" between new academies and the Education Secretary will state that the school has the right to employ staff who they believe are properly qualified, even if they do not have QTS.
Academies that are already open can ask for this clause to be included in their agreement.
The Department for Education (DfE) said that the move brings academies in line with private schools, and the Government's flagship free schools.
It means that academies can hire professionals such as scientists, engineers, musicians and linguists who may not have QTS status.
Christine Blower, general secretary of the National Union of Teachers, said it was a "perverse decision by the DfE and a clear dereliction of duty."
""The NUT believes all children deserve to be taught by qualified teachers," she argued.
Blower said that a poll conducted by the union last year found that 89% of parents want a qualified teacher to teach their child.
"Parents and teachers will see this as a cost-cutting measure that will cause irreparable damage to children's education," she said.
"Schools need a properly resourced team of qualified teachers and support staff, not lower investment dressed up as 'freedoms'."
A DfE spokesman said: "Independent schools and free schools can already hire brilliant people who have not got QTS.
"We are extending this flexibility to all academies so more schools can hire great linguists, computer scientists, engineers and other specialists who have not worked in state schools before.
"We expect the vast majority of teachers will continue to have QTS. This additional flexibility will help schools improve faster. No existing teacher contract is affected by this minor change."
Academies are semi-independent state schools that receive funding directly, rather than through a local authority, and have more freedom over areas such as pay and conditions and the curriculum.