Four out of 10 special schools claim that budget constraints are making it difficult for them to meet their legal obligations to pupils with special needs, according to the NCPTAreport.
And more than seven out of 10 local authority secondaries - 1,115 schools - say that they are able to meet the requirements of the special needs code of practice only "with difficulty".
One-fifth of youngsters are estimated to have a special need at some time during their school life.
The NCPTA says that it is "shameful" that so many schools have difficulty in fulfilling the code of practice. It wants an immediate review of the code and more funding to give teachers additional training in supporting pupils with special needs and to employ other specialists.