Not all PTA's are registered NPO's. So one needs to check that. If they are registered, then it depends on the nature of the payment.
- If mandatory dues, it's not deductible.
- If a payment for a product or service that you or the student receives in return, it's not deductible. (For example, a field trip)
- If you have no say in how your contribution is used, then it's deductible as a charitable donation if the PTA is a registered NPO.