Schools are being urged by the Local Government Association to make sure parents can shop around for school uniforms.
The LGA says schools should use two or more suppliers in an effort to keep costs down.
While school uniform items are sold in supermarkets inexpensively, some schools still have uniforms which are only available from specialist suppliers.
The LGA quotes a recent survey finding that 17% of parents and carers could only get the uniform and PE kit their children needed from a single designated shop or via the school itself.
Guidance introduced two years ago warned schools they could face challenges under the Competition Act if they only used one supplier.
Council leaders are now urging parents to do more to hold their school governors to account for decisions on uniform policy.
The LGA has published a three-point plan it believes all schools should adhere to in order to help parents reduce the impact of school uniform costs.
uniform items should all be available from a minimum of two different suppliers, not counting the school itself
school symbols and logos should be available as sew-on patches
parents should be given opportunities to buy and sell second hand uniform from other parents
LGA chair Margaret Eaton said: “Many councils offer grants to families struggling to pay for uniform, but schools have the power to reduce this burden for both parents and taxpayers.
“Offering uniforms from a number of retailers and making it easier to attach logos to widely available clothing lets schools keep their individuality while bringing in the necessary competition to keep costs down.”
School uniform research published by DCSF in February 2009